LED chip transfer method and display panel

Abstract

The present application relates to an LED chip transfer method and a display panel, the chip transfer method including: providing a drive substrate (10) having at least one pair of bonding points, the pair of bonding points including a first bonding point (101) and a second bonding point (102); forming a compensation layer (103) on the drive substrate (10) to cover the first bonding point (101) and the second bonding point (102); providing a chip substrate including a base substrate (201) and a plurality of chips (30); and performing a first alignment process to form a first groove (103a) and a second groove (103b) in the compensation layer (103); the second groove (103b) being aligned with the first groove. (103a) and spaced apart from each other - forming a first via hole (103c) and a second via hole (103d) spaced apart from each other from the first groove (103a) and the second groove (103b) in the compensation layer; forming a first transfer electrode (401) and a second transfer electrode (402) disconnected from each other in the compensation layer (103); inserting a first pin (302) into the first groove (103a) to bind it to the first transfer electrode (401), and inserting a second pin (303) into the second groove (103b) to bind it to the second transfer electrode (402); and peeling the base substrate (201) from the chip (30).

Description

Priority claim

[0001] This application claims priority to a Chinese patent application bearing application number CN202211197908.7 and entitled "LED chip transfer method and display panel" filed with the China Patent Office on September 29, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present application relates to the field of display technology, and in particular to an LED chip transfer method and a display panel. [Background technology]

[0003] Micro-LED is a new generation display technology that has higher photoelectric efficiency, higher brightness, higher contrast, and lower power consumption than traditional LCD displays, and can be combined with flexible panels to realize flexible displays.

[0004] Micro-LED (micro light emitting diode) chips are light emitting diode chips with a size of less than 100 microns. Typically, after the fabrication of micro light emitting diode chips is completed, a mass transfer process is required to transfer a large number of micro light emitting diode chips (usually tens of thousands to hundreds of thousands) to a driving circuit board. However, currently, micro light emitting diode chips have a tilt problem, which causes them to be abnormally bound to the driving circuit board. Summary of the Invention

[0005] The present application provides an LED chip transfer method and a display panel that can ensure normal binding between the LED chip and the driving substrate, improve the transfer accuracy of the micro light-emitting diode chip, and ensure the yield of the display panel.

[0006] A first aspect of the present application provides an LED chip transfer method, the chip transfer method comprising: providing a drive substrate having at least one set of coupling points, the set of coupling points including a first coupling point and a second coupling point; forming a compensation layer on the drive substrate to cover the first coupling point and the second coupling point; providing a chip substrate including a base substrate and a plurality of chips, each chip including a chip body, a first pin, and a second pin, the first pin and the second pin being provided on a side of the chip body away from the base substrate; performing a first alignment process on the chip substrate and the drive substrate, and forming a first groove in the compensation layer using the first pins and a second groove in the compensation layer using the second pins, the second groove being spaced apart from the first groove; After forming the first groove and the second groove in the compensation layer, patterning the compensation layer to form a first via hole and a second via hole in the compensation layer spaced apart from the first groove and the second groove, the first via hole exposing at least a portion of the first bonding point and the second via hole exposing at least a portion of the second bonding point; forming a first transfer electrode and a second transfer electrode disconnected from each other on the compensation layer, the first transfer electrode being partially located in the first groove and partially connected to the first coupling point through the first via hole, and the second transfer electrode being partially located in the second groove and partially connected to the second coupling point through the second via hole; performing a second alignment process on the chip substrate and the drive substrate so that the first pins are inserted into the first grooves and bound to the first transfer electrodes, and the second pins are inserted into the second grooves and bound to the second transfer electrodes; After the chip substrate and the drive substrate are subjected to a second alignment process, the base substrate is peeled off from the chip.

[0007] A second aspect of the present application provides a display panel, The display panel includes a driving substrate, a chip, a compensation layer, a first transfer electrode, and a second transfer electrode; the drive substrate has at least one set of coupling points, the set of coupling points including a first coupling point and a second coupling point; the chip includes a chip body, a first pin, and a second pin, the first pin and the second pin are both connected to the chip body and spaced apart; the compensation layer is provided on the drive substrate and covers the first coupling points and the second coupling points, the compensation layer is provided with first grooves and second grooves that are spaced apart; a portion of the first transfer electrode is connected to the first connection point through a first via hole and a portion of the first transfer electrode is located within the first groove; The second transfer electrode is provided on the compensation layer at a distance from the first transfer electrode, and the second transfer electrode is connected to the second connection point through a second via hole, and a portion of the second transfer electrode is located within the second groove.

[0008] The present application includes an LED chip transfer method and a display panel, which includes: installing a compensation layer on a driving substrate; bonding a chip substrate having an LED chip to the compensation layer; forming first and second grooves in the compensation layer that fit the contours of the first and second pins of the LED chip; removing the chip substrate having the LED chip; forming first and second transfer electrodes on the compensation layer, which are connected to the first and second bonding points, respectively; bonding the chip substrate having the LED chip to the driving substrate; inserting the first and second pins of the LED chip into the first and second grooves to bind with the first and second bonding points, respectively. This effectively solves the binding problem between the LED chip and the driving substrate due to differences in horizontal height or tilt of the LED chip on the chip substrate, improves the success rate of LED chip transfer, improves the transfer accuracy of the LED chip and the driving substrate, and further improves the display effect of the display panel.

[0009] Other features and advantages of the present application will be apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0010] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. [Brief explanation of the drawings]

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without creative efforts. [Figure 1] FIG. 1 shows a schematic flow chart of the LED chip transfer method provided by Embodiment 1 of the present application. [Figure 2] FIG. 2 shows a schematic structural diagram of adding a compensation layer to the driving substrate provided by Embodiment 1 of the present application. [Figure 3] FIG. 3 shows a schematic structural diagram of a chip substrate and a driver substrate having chips provided by Embodiment 1 of the present application. [Figure 4] FIG. 4 shows a schematic structural diagram of a chip inserted into the compensation layer provided by Embodiment 1 of the present application. [Figure 5] FIG. 5 shows a schematic structural diagram of removing the chip substrate and forming the grooves provided by the first embodiment of the present application. [Figure 6] FIG. 6 shows a schematic structural diagram of adding a first via hole and a second via hole to the compensation layer provided by Embodiment 1 of the present application. [Figure 7] FIG. 7 shows a schematic structural diagram of adding a first transfer electrode and a second transfer electrode to the compensation layer provided by the first embodiment of the present application. [Figure 8] FIG. 8 shows a schematic structural diagram of locating under-bump metal and In / Sn dots in the grooves provided by the first embodiment of the present application. [Figure 9] FIG. 9 shows a schematic structural diagram of the binding between the tip and the In / Sn point provided by embodiment 1 or embodiment 2 of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, exemplary embodiments will be described in more detail with reference to the accompanying drawings. However, exemplary embodiments may be embodied in various forms and should not be understood as being limited to the examples described herein. On the contrary, these embodiments are provided to make the present application more comprehensive and complete and to fully convey the concept of exemplary embodiments to those skilled in the art.

[0013] In this application, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of those features. In this description, "plurality" means two or more, unless expressly and specifically limited.

[0014] In this application, unless otherwise clearly stated or limited, the terms "assembled," "connected," and the like should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, an internal connection between two elements, or an interactive relationship between two elements. The specific meanings of the above terms in this specification can be understood by those skilled in the art depending on the context.

[0015] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of the embodiments of the present application. However, those skilled in the art will understand that the technical solutions of the present application may be implemented without one or more of the specific details, or may employ other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the present application.

[0016] Embodiment 1 During the mass transfer process of LED chips 30, a weak adhesive is used on the side of the substrate where the LED chips 30 are attached. This makes it easy for distortion to occur on the side of the substrate closest to the LED chips 30 when the LED chips 30 are attached. During the process of attaching the LED chips 30 to the substrate, different pressures are applied to different parts of the substrate, causing each LED chip 30 to contact the substrate at different positions. This can result in some LED chips 30 being deeply pressed, some being shallowly pressed, and some being tilted. As a result, when the LED chips 30 are bound to the drive substrate 10, the LED chips 30 are not at the same level, so the pins of some LED chips 30 cannot effectively bind to the bonding points on the drive substrate 10. This can prevent the LED chips 30 from being detached from the chip substrate, resulting in transfer failure. Alternatively, the LED chips 30 may emit abnormal light due to improper contact between the binding pins bound to the drive substrate 10 and the bonding points.

[0017] Therefore, to solve the problem of failure in transferring the LED chip 30, the embodiment of the present application provides a method for transferring the LED chip 30, as shown in FIG. 1, which includes the following steps.

[0018] In S100, as shown in FIG. 2, a driving substrate 10 having at least one set of coupling points is provided, where the set of coupling points includes a first coupling point 101 and a second coupling point 102.

[0019] For example, the transistors in this drive substrate 10 can be made of amorphous silicon (A-Si), low temperature polysilicon (LTPS), indium gallium zinc oxide (IGZO), or single crystal silicon MOS. Among these, amorphous silicon material is of low quality and has low carrier mobility, so the current density that amorphous silicon transistors can withstand is low, but low temperature polysilicon and indium gallium zinc oxide have high carrier mobility and can withstand high current densities.

[0020] The first connecting point 101 is the drain of a transistor or MOS tube on the driving substrate 10, and the second connecting point 102 is a common signal line on the driving substrate 10. The first connecting point 101 can provide a positive voltage to the LED chip 30, and the second connecting point 102 can provide a negative voltage. The first connecting point 101 and the second connecting point 102 are arranged on the same layer.

[0021] The phrase "disposed in the same layer" refers to a layer structure formed by forming a film layer for forming a specific pattern using the same film formation process and then performing a single patterning step using the same mask. In other words, one patterning step corresponds to one mask (also called a photomask). Depending on the specific pattern, one patterning step may include multiple exposure, development, or etching processes. The specific pattern within the formed layer structure may be continuous or discontinuous, and these specific patterns may be at different heights or have different thicknesses. This simplifies the manufacturing process, reduces manufacturing costs, and improves production efficiency.

[0022] In step S200, as shown in FIG. 2, the compensation layer 103 covering the first connection points 101 and the second connection points 102 is formed on the driving substrate 10.

[0023] 3, a chip substrate is provided, which includes a base substrate 201 and a plurality of LED chips 30. The LED chip 30 includes a chip body 301, a first pin 302, and a second pin 303, and the first pin 302 and the second pin 303 are provided on the side of the chip body 301 that is away from the base substrate 201.

[0024] The chip substrate may have a substrate structure formed by growing the LED chip 30 directly on a wafer, or may have a substrate structure in which the LED chip 30 is grown on a wafer, and then the LED chip 30 is attached to the chip substrate and transferred to the drive substrate 10.

[0025] The growth substrate to which the substrate is transferred by the transfer method includes a base substrate 201 and a transfer layer 202. The transfer layer 202 is provided on one side of the base substrate 201 and connected to the chip body 301. Here, the base substrate 201 can be made of organic glass, resin, quartz, sapphire, or the like, and its material is not particularly limited. The transfer layer 202 can be made of a weakly adhesive material such as polydimethylsiloxane (PDMS).

[0026] In step S400, as shown in FIG. 4, a first alignment process is performed on the chip substrate and the drive substrate 10, and a first groove 103a is formed in the compensation layer 103 using a first pin 302, and a second groove 103b is formed in the compensation layer 103 using a second pin 303, and the second groove 103b and the first groove 103a are spaced apart from each other.

[0027] The chip substrate may be the same size as the driving substrate 10, which makes it more convenient and quick to transfer the LED chip 30. The number of grooves corresponds one-to-one to the LED chip 30 pins of the LED chip 30 on the chip substrate.

[0028] Furthermore, after the first alignment process is performed, external pressure is applied to the chip substrate toward the drive substrate 10, pressing at least a portion of the first pins 302 and the second pins 303 into the compensation layer 103, thereby forming first grooves 103a and second grooves 103b in the compensation layer 103 with the same contours as the first pins 302 and the second pins 303. In this way, pressure bonding makes it easier to form the same contours in the compensation layer 103 as the pins of the LED chip 30, making it easier to connect the LED chip 30 to the bonding points and improving the success rate of transferring the LED chip 30.

[0029] Furthermore, after applying external pressure to the chip substrate toward the drive substrate 10, portions of the first pin 302 and the second pin 303 are pressed into the compensation layer 103, and other portions are positioned so as to protrude relative to the surface of the compensation layer 103 away from the drive substrate 10.

[0030] When the driving substrate 10 and the chip substrate are bonded together under pressure, the first pin 302 and the second pin 303 are partially inserted into the compensation layer 103 to prevent the first pin 302 and the second pin 303 from being inserted too deeply, which could damage the transistor structure, affect the operating state of the LED chip 30, or prevent the LED chip 30 from being inserted too deeply and becoming stuck. If the first pin 302 and the second pin 303 are inserted too shallowly, the transfer electrodes may become ineffective, which may affect the connection between the LED chip 30 and the connection point.

[0031] The first pin 302 and the second pin 303 of the LED chip 30 have the same pin height, i.e., they are located in the same horizontal plane.

[0032] Furthermore, the thickness of the compensation layer 103 is greater than the height of the pins of the LED chip 30, or the thickness of the compensation layer 103 is greater than the overall height of the LED chip 30. In this way, the LED chip 30 can be effectively protected, and the LED chip 30 can be prevented from being inserted too deeply and damaging the transistor.

[0033] For example, the compensation layer 103 may be 2 to 4 μm, such as 2 μm, 3 μm, or 4 μm. However, it should be understood that if the compensation layer 103 is too thick, the cost will be high and it will be difficult to open the first via hole 103c and the second via hole 103d, and if the compensation layer 103 is too thin, compensation will be difficult and there will be a problem of the pin of the LED chip 30 piercing through it.

[0034] Furthermore, in step S500, as shown in Figures 5 and 6, after forming a first groove 103a and a second groove 103b in the compensation layer 103, the compensation layer 103 is patterned to form a first via hole 103c and a second via hole 103d in the compensation layer 103, spaced apart from the first groove 103a and the second groove 103b, so that the first via hole 103c exposes at least a portion of the first bonding point 101 and the second via hole 103d exposes at least a portion of the second bonding point 102.

[0035] For example, the compensation layer 103 is exposed, developed, and etched to form a first via hole 103c and a second via hole 103d spaced apart from each other, with the first groove 103a and the second groove 103b located between the first via hole 103c and the second via hole 103d. In this way, the design of the first groove 103a and the second groove 103b is more convenient, which is helpful for opening the first via hole 103c and the second via hole 103d, and avoids interference between them and affecting the transfer process of the LED chip 30.

[0036] One LED chip 30 corresponds to one first via hole 103c and one second via hole 103d.

[0037] Furthermore, when the chip substrate is separated, the LED chip 30 is not bonded to the first bonding points 101 and the second bonding points 102 on the driving substrate 10, and the friction force of the grooves on the pins of the LED chip 30 is smaller than the adhesive force between the transfer layer 202 and the LED chip 30. In this way, the pins of the LED chip 30 can be released from the grooves of the compensation layer 103 just as the LED chip 30 is released from the grooves, which facilitates the subsequent formation of transfer electrodes.

[0038] Furthermore, the orthogonal projections of the first groove 103a and the second groove 103b formed by one LED chip 30 on the driving substrate 10 do not at least partially overlap with the orthogonal projections of the first connecting point 101 and the second connecting point 102 on the driving substrate 10. This effectively ensures the opening of the grooves and the first via hole 103c and the second via hole 103d, and avoids the problem of the first pin 302 and the second pin 303 piercing and damaging the first connecting point 101 and the second via hole 103d.

[0039] In step S600, as shown in FIG. 7, a first transfer electrode 401 and a second transfer electrode 402 that are disconnected from each other are formed on the compensation layer 103, and the first transfer electrode 401 is partially located within the first groove 103a and partially connected to the first connection point 101 via the first via hole 103c, and the second transfer electrode 402 is partially located within the second groove 103b and partially connected to the second connection point 102 via the second via hole 103d.

[0040] For example, a film is formed on the compensation layer 103, and then exposed, developed, and etched to form a first transfer electrode 401 and a second transfer electrode 402 that are spaced apart from each other. A portion of the first transfer electrode 401 is located in the first groove 103a, a portion of it is connected to the first node 101 through the first via hole 103c, and the remaining portion is located in the compensation layer 103. A portion of the second transfer electrode 402 is located in the second groove 103b, a portion of it is connected to the second node 102 through the second via hole 103d, and the remaining portion is located in the compensation layer 103. It can be seen that the first transfer electrode 401 and the second transfer electrode 402 located in the compensation layer 103 are spaced apart from each other.

[0041] Optionally, a film is formed on the compensation layer 103 by physical vapor deposition (PVD), and a first transfer electrode 401 and a second transfer electrode 402 are formed by photolithography, and the first transfer electrode 401 flows into the first via hole 103c and is connected to the first connection point 101, and the first transfer electrode 401 flows into the second via hole 103d and is connected to the second connection point 102, so as to provide positive and negative voltages to the LED chip 30 respectively.

[0042] The material of the first transfer electrode 401 and the second transfer electrode 402 is not particularly limited, and may be ITO (indium tin oxide), IGZO (indium gallium zinc oxide), or the like.

[0043] In step S700, as shown in Figures 1, 8, and 9, a second alignment process is performed on the chip substrate and the drive substrate 10, and the first pin 302 is inserted into the first groove 103a and bound to the first transfer electrode 401, and the second pin 303 is inserted into the second groove 103b and bound to the second transfer electrode 402.

[0044] This allows the first pin 302 of the LED chip 30 to be connected to the first connection point 101 via the first transfer electrode 401, and the second pin 303 to be connected to the second connection point 102 via the second transfer electrode 402, so as to provide positive and negative voltages to the LED chip 30.

[0045] In this application, a compensation layer 103 is added to the driving substrate 10, and the first pins 302 and second pins 303 of the chip substrate are bonded to the compensation layer 103. First grooves 103a and second grooves 103b having the same contours as the first pins 302 and second pins 303 are formed in the compensation layer 103. The first pins 302 and second pins 303 are then connected to the first bonding points 101 and second bonding points 102 via the first transfer electrodes 401 and second transfer electrodes 402. This solves the problem of binding abnormalities caused by differences in horizontal height or tilt of the LED chip 30 bonded to the chip substrate, and further improves the transfer accuracy of the LED chip 30 and the driving substrate 10, thereby improving the tightness of the connection between the pins of the LED chip 30 and the bonding points.

[0046] Furthermore, the step of forming a compensation layer 103 covering the first coupling points 101 and the second coupling points 102 on the driving substrate 10 includes: forming a curable material on the drive substrate; This includes pre-curing the curable material to form the compensation layer 103.

[0047] For example, the compensation layer 103 can be made of an organic material such as polyimide (PI) or polymethyl methacrylate (PMMA). When the organic material is baked in a vacuum environment at a temperature of 60°C to 90°C for 50 to 90 seconds, most of the solvent in the organic material evaporates, transforming the organic material from a liquid state to a semi-solid state, allowing the compensation layer 103 to remain flexible and deformable. In other words, by pre-curing the compensation layer 103, first grooves 103a and second grooves 103b having the same contours as the first pins 302 and second pins 303 can be effectively formed in the compensation layer 103.

[0048] Optionally, the organic material can be baked at a temperature of 60° C. for 90 seconds in a vacuum environment to volatilize most of the solvent in the organic material and change the organic material from a liquid state to a semi-solid state.

[0049] Alternatively, the organic material can be baked in a vacuum environment at a temperature of 70° C. for 70 seconds to volatilize most of the solvent in the organic material and change the organic material from a liquid state to a semi-solid state.

[0050] Alternatively, the organic material can be baked in a vacuum environment at a temperature of 90°C for 50 seconds to volatilize most of the solvent in the organic material and change the organic material from a liquid state to a semi-solid state.

[0051] In order to improve the stability of the compensation layer 103, after applying an external pressure to the chip substrate toward the drive substrate 10 and before patterning the compensation layer 103, the transfer method may further include: The method includes separating the first pin 302 and the second pin 303 from the compensation layer 103, and then curing the compensation layer 103, where the hardness of the compensation layer 103 after the curing process is greater than the hardness of the compensation layer 103 after the temporary curing process.

[0052] It can be seen that removing the first pin 302 and the second pin 303 from the compensation layer 103 means separating the chip substrate having the LED chip 30 from the driving substrate 10, and then curing the compensation layer 103 in which the first groove 103a and the second groove 103b are opened.

[0053] To harden the compensation layer 103, for example, the semi-solid compensation layer 103 is baked at a temperature of 180°C to 250°C for 20 to 30 minutes to harden it, forming the grooves and preventing the grooves from collapsing and affecting the insertion of the pins of the LED chip 30.

[0054] Optionally, the semi-solid compensation layer 103 is baked at a temperature of 180° C. for 30 minutes to harden the compensation layer 103 .

[0055] Alternatively, the semi-solid compensation layer 103 may be baked at a temperature of 200° C. for 25 minutes to harden the compensation layer 103 .

[0056] Alternatively, the semi-solid compensation layer 103 may be baked at a temperature of 250° C. for 20 minutes to harden the compensation layer 103 .

[0057] It should be noted that, since the compensation layer 103 may shrink when heated, the actual widths of the first groove 103a and the second groove 103b formed in the compensation layer 103 are greater than the widths of the first pin 302 and the second groove, so that the reinsertion of the first pin 302 and the second pin 303 is smoother and more convenient and less likely to cause damage to the pins of the LED chip 30.

[0058] 8 and 9, after forming the first transfer electrode 401 and the second transfer electrode 402 cut from each other on the compensation layer 103, and before the chip substrate and the driving substrate 10 are subjected to a second alignment process, the transfer method further includes forming a solder layer in the first groove 103a and the second groove 103b.

[0059] The first pin 302 and the second pin 303 are welded to the first transfer electrode 401 and the second transfer electrode 402 via a solder layer, and at the same time, the first transfer electrode 401 is connected to the first connection point 101 and the second transfer electrode 402 is connected to the second connection point 102. Therefore, the pins of the LED chip 30 are connected to the first connection point 101 and the second connection point 102, respectively, and receive the positive and negative voltages supplied from the first connection point 101 and the second connection point 102.

[0060] For example, an under bump metal (UBM) 501 is formed in the first groove 103a and the second groove 103b of the compensation layer 103 by evaporation and photolithography, and then an In / Sn point 502 is formed on the under bump metal (UBM) 501 to be used as a binding point between the first pin 302 and the second pin 303 and the first transfer electrode 401 and the second transfer electrode 402.

[0061] It can be seen that the under bump metal (UBM) 501 and In / Sn dots 502 formed in the first groove 103a and the second groove 103b are at the same inclined position and horizontal height as the first pin 302 and the second pin 303 on the chip substrate. This matching improves the binding effect between the first pin 302 and the second pin 303 and the first connecting point 101 and the second connecting point 102, thereby improving the transfer success rate of the LED chip 30 and ensuring that the pins of the LED chip 30 are effectively bound to the driving substrate 10, thereby ensuring that the LED chip 30 emits light normally.

[0062] Also, as shown in Figure 9, after the second alignment process is performed on the chip substrate and the drive substrate 10 and the first pin 302 and the second pin 303 are inserted into the first groove 103a and the second groove 103b, respectively, the transfer method further includes sequentially performing a melting process and a cooling and hardening process on the solder layer in the first groove 103a and the second groove 103b so that the first pin 302 and the second pin 303 are bound to the first transfer electrode 401 and the second transfer electrode 402, respectively.

[0063] For example, when the first pin 302 and the second pin 303 are inserted into the grooves, the In / Sn dots 502 are also heated to melt and then cooled to harden, so that the In / Sn dots 502 in the first groove 103a are welded to the first pin 302 and the In / Sn dots 502 in the second groove 103b are welded to the second pin 303. Here, the fixing force between the In / Sn dots 502 and the pins of the LED chip 30 is greater than the adhesive force of the chip substrate to the LED chip 30, so the chip substrate is detached from the LED chip 30, and the transfer of the LED chip 30 is completed.

[0064] The solder layers in the first groove 103a and the second groove 103b may be melted sequentially by inserting the first pin 302 and the second pin 303 into the first groove 103a and the second groove 103b, heating and melting the solder layers, and welding the first pin 302 and the second pin 303. The specific process is not particularly limited.

[0065] Furthermore, heating and melting can be carried out until the temperature reaches the melting point of In / Sn or higher, such as 260°C or 270°C.

[0066] Furthermore, in the embodiment of the present application, the compensation layer 103 is made of polyimide (PI) or polymethyl methacrylate (PMMA), which can effectively prevent the compensation layer 103 from being decomposed or deformed when In / Sn melts. Of course, the compensation layer 103 can also be made of other organic materials with good thermal stability, and is not particularly limited.

[0067] In step S800, as shown in FIGS. 1 and 9, after the second alignment process between the chip substrate and the driving substrate 10, the base substrate 201 is peeled off from the LED chip 30.

[0068] It can be seen that by removing the base substrate 201 when the first pin 302 and the second pin 303 are welded to the solder layers, the base substrate 201 and the LED chip 30 can be easily separated.

[0069] Embodiment 2 The second embodiment of the present application provides a display panel including a driving substrate 10, an LED chip 30, a first transfer electrode 401, a second transfer electrode 402 and a compensation layer 103, as shown in FIG.

[0070] Here, the driving substrate 10 has at least one set of connection points, and the set of connection points includes a first connection point 101 and a second connection point 102, where the first connection point 101 may be the drain of a transistor, and the second connection point 102 may be a common signal line arranged in the same layer as the drain.

[0071] The LED chip 30 includes a chip body 301, a first pin 302 and a second pin 303, both of which are connected to the chip body 301 and spaced apart.

[0072] The compensation layer 103 is provided on the drive substrate 10 and covers the first coupling points 101 and the second coupling points 102, and the compensation layer 103 is provided with a first groove 103a and a second groove 103b arranged at an interval.

[0073] A part of the first transfer electrode 401 is connected to the first connection point 101 through the first via hole 103 c , a part is located in the first groove 103 a , and the remaining part is located in the compensation layer 103 .

[0074] A portion of the second transfer electrode 402 is connected to the second connection point 102 through the second via hole 103 d , a portion is located in the second groove 103 b , and the remaining portion is located in the compensation layer 103 .

[0075] The compensation layer 103 has a first groove 103a and a second groove 103b that fit the first pin 302 and the second pin 303. When the first pin 302 and the second pin 303 are inserted into the first groove 103a and the second groove 103b, they are connected to the first connection point 101 and the second connection point 102 via the first transfer electrode 401 and the second transfer electrode 402, respectively, thereby supplying positive and negative voltages to the LED chip 30, and the LED chip 30 displays normally.

[0076] In this way, by adding transfer electrodes and solder points to the first groove 103a and the second groove 103b, which have the same contours as the first pin 302 and the second pin 303, the first pin 302 and the second pin 303 are stably connected to the first bonding point 101 and the second bonding point 102, ensuring the tightness of the connection between the first pin 302 and the second pin 303 and the first bonding point 101 and the second bonding point 102, effectively solving the problems of transfer accuracy and binding abnormalities between the LED chip 30 and the driving substrate 10, and further improving the display effect of the display panel.

[0077] 9, the thickness of the compensation layer 103 must be thicker than the thickness of the first pin 302 and the second pin 303. In this way, the LED chip 30 can be effectively protected and the LED chip 30 can be prevented from being inserted too deeply and damaging the transistor.

[0078] 9, the orthogonal projections of the first connecting point 101 and the second connecting point 102 on the drive substrate 10 do not at least partially overlap with the orthogonal projections of the first pin 302 and the second pin 303 on the drive substrate 10. This does not affect the opening of the first groove 103a, the second groove 103b, the first via hole 103c, and the second via hole 103d, and also avoids the problem of the first pin 302 and the second pin 303 piercing and damaging the first connecting point 101 and the second via hole 103d.

[0079] Furthermore, an under bump metal (UBM) 501 and an In / Sn dot 502 are included in the first groove 103a and the second groove 103b, which are the same as the first pin 302 and the second pin 303, formed in the compensation layer 103. The In / Sn dot 502 is welded to the first pin 302 or the second pin 303, and is connected to the first transfer electrode 401 or the second transfer electrode 402 via the under bump metal (UBM) 501.

[0080] The horizontal height and inclination angle formed by the under bump metal (UBM) 501 and the In / Sn dots 502 located in the first groove 103a and the second groove 103b are the same as those of the first pin 302 and the second pin 303, thereby ensuring the accuracy of the connection between the first pin 302 and the second pin 303 and the first transfer electrode 401 and the second transfer electrode 402, ensuring the light emission of the LED chip 30, and further ensuring the display effect of the display panel.

[0081] In the description herein, the use of terms such as "some embodiments," "exemplary," and the like means that a particular feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present application. In the present specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine different embodiments or examples and features of different embodiments or examples described herein, as long as they are not mutually inconsistent.

[0082] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are illustrative and should not be construed as limiting the present application. Those skilled in the art can change, modify, substitute and change the above embodiments within the scope of the present application, so that any changes or modifications made in accordance with the claims and descriptions of the present application shall fall within the scope of the patent of the present application.

Claims

1. An LED chip transfer method, comprising: The chip transfer method includes: providing a drive substrate having at least one set of bonding points, the set of bonding points including a first bonding point and a second bonding point; forming a compensation layer on the drive substrate to cover the first coupling point and the second coupling point; providing a chip substrate including a base substrate and a plurality of chips, each chip including a chip body, a first pin, and a second pin, the first pin and the second pin being provided on a side of the chip body away from the base substrate; performing a first alignment process on the chip substrate and the drive substrate, and forming a first groove in the compensation layer using the first pins and a second groove in the compensation layer using the second pins, the second groove being spaced apart from the first groove; after forming the first groove and the second groove in the compensation layer, patterning the compensation layer to form a first via hole and a second via hole in the compensation layer spaced apart from the first groove and the second groove, the first via hole exposing at least a portion of the first bonding point and the second via hole exposing at least a portion of the second bonding point; forming a first transfer electrode and a second transfer electrode disconnected from each other on the compensation layer, the first transfer electrode being partially located in the first groove and partially connected to the first coupling point through the first via hole, and the second transfer electrode being partially located in the second groove and partially connected to the second coupling point through the second via hole; performing a second alignment process on the chip substrate and the drive substrate so that the first pins are inserted into the first grooves and bound to the first transfer electrodes, and the second pins are inserted into the second grooves and bound to the second transfer electrodes; and peeling the base substrate from the chip after a second alignment process is performed on the chip substrate and the drive substrate. The LED chip transfer method is characterized by the above.

2. forming a first groove in the compensation layer using the first pin and a second groove in the compensation layer using the second pin; and applying an external pressure to the chip substrate toward the drive substrate after the chip substrate and the drive substrate are subjected to a first alignment process, thereby pressing at least a portion of the first pin and the second pin into the compensation layer to form the first groove and the second groove.

2. The LED chip transfer method according to claim 1.

3. After applying an external pressure to the chip substrate toward the drive substrate, a portion of the first pin and the second pin are pressed into the compensation layer, and another portion of the first pin and the second pin are arranged to protrude toward a surface of the compensation layer remote from the drive substrate.

3. The LED chip transfer method according to claim 2.

4. forming a compensation layer on the drive substrate that covers the first coupling points and the second coupling points; forming a curable material on the drive substrate; and pre-curing the curable material to form a compensation layer.

3. The LED chip transfer method according to claim 2.

5. After applying an external pressure to the chip substrate toward the drive substrate and before patterning the compensation layer, the transfer method includes: separating the first pin and the second pin from the compensation layer, and then curing the compensation layer; The hardness of the compensation layer after the hardening treatment is greater than the hardness of the compensation layer after the pre-hardening treatment.

5. The LED chip transfer method according to claim 4.

6. The curable material is polyimide or polymethyl methacrylate, the preliminary curing treatment and the curing treatment are baking treatments, and the baking temperature of the preliminary curing treatment is lower than the baking temperature of the curing treatment.

6. The LED chip transfer method according to claim 5.

7. The temporary curing treatment of the curable material includes: and baking the curable material in a vacuum environment at a temperature of 60°C to 90°C for 50 to 90 seconds to change the curable material from a liquid state to a semi-solid state.

7. The LED chip transfer method according to claim 6.

8. The temporary curing treatment of the curable material includes: baking the curable material at a temperature of 70°C for 70 seconds in a vacuum environment to change the curable material from a liquid state to a semi-solid state.

7. The LED chip transfer method according to claim 6.

9. curing the compensation layer and hardening the semi-solid compensation layer by baking it at 180°C to 250°C for 20 to 30 minutes to form the first groove and the second groove.

7. The LED chip transfer method according to claim 6.

10. curing the compensation layer and curing the semi-solid compensation layer by baking at 200° C. for 25 minutes to form the first groove and the second groove.

7. The LED chip transfer method according to claim 6.

11. After the compensation layer is heated and shrunk, the actual widths of the first groove and the second groove formed in the compensation layer are greater than the widths of the first pin and the second pin.

7. The LED chip transfer method according to claim 6.

12. After forming the first transfer electrode and the second transfer electrode, which are cut from each other, on the compensation layer and before performing a second alignment process on the chip substrate and the drive substrate, the transfer method further includes forming a solder layer in the first groove and the second groove; After a second alignment process is performed on the chip substrate and the drive substrate so that the first pins and the second pins are inserted into the first grooves and the second grooves, respectively, the transfer method includes sequentially performing a melting process and a cooling and hardening process on the solder layers in the first grooves and the second grooves so that the first pins and the second pins are bound to the first transfer electrodes and the second transfer electrodes, respectively.

2. The LED chip transfer method according to claim 1.

13. The second bonding point and the second bonding point are disposed in the same layer.

2. The LED chip transfer method according to claim 1.

14. The thickness of the compensation layer is 2 to 4 μm.

2. The LED chip transfer method according to claim 1.

15. The compensation layer is formed by physical vapor deposition.

2. The LED chip transfer method according to claim 1.

16. A display panel, a driving substrate, a chip, a compensation layer, a first transfer electrode, and a second transfer electrode; the drive substrate has at least one set of coupling points, the set of coupling points including a first coupling point and a second coupling point; the chip includes a chip body, a first pin, and a second pin, the first pin and the second pin are both connected to the chip body and spaced apart; the compensation layer is provided on the drive substrate and covers the first coupling points and the second coupling points, the compensation layer is provided with first grooves and second grooves that are spaced apart; a portion of the first transfer electrode is connected to the first connection point through a first via hole and a portion of the first transfer electrode is located within the first trench; The second transfer electrode is provided on the compensation layer at a distance from the first transfer electrode, and the second transfer electrode is connected to the second connection point through a second via hole, and a portion of the second transfer electrode is located within the second groove. A display panel characterized by:

17. The first pin and the second pin have the same thickness, and the compensation layer has a thickness greater than the thickness of the first pin and the second pin.

17. The display panel according to claim 16.

18. An orthogonal projection of the first coupling point and the second coupling point on the drive substrate does not at least partially overlap with an orthogonal projection of the first pin and the second pin on the drive substrate.

17. The display panel according to claim 16.

19. The first groove and the second groove are located between the first via hole and the second via hole.

19. The display panel according to claim 18.

20. The second bonding point and the second bonding point are disposed in the same layer.

17. The display panel according to claim 16.

Images