Chip transfer method and display panel

Abstract

The present application relates to a chip transfer method and a display panel. The chip transfer method comprises the following steps: providing a chip carrier plate; forming a temporary bonding structure, the temporary bonding structure comprising a bonding layer arranged on a chip and a through hole arranged on the chip carrier plate, the bonding layer being connected with an inner wall of the through hole; removing a buffer layer on the chip connected with the chip carrier plate, the bonding layer keeping the chip on the chip carrier plate; arranging a target substrate and the chip carrier plate so that a side of the chip carrier plate provided with the chip is opposite to a side of the target substrate for arranging the chip; and disconnecting the bonding layer arranged on a chip to be transferred from the through hole so that the chip to be transferred is separated from the chip carrier plate and falls to the target substrate. The stability of the chip when peeling off the chip carrier plate is improved, thereby ensuring the accuracy of the chip transfer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chip transfer, in particular to a chip transfer method and a display panel. BACKGROUND

[0002] Micro-LED (Micro Light-Emitting Diode) is an emerging display technology. Compared with conventional display technologies, display technologies based on Micro-LED technology have the characteristics of fast response speed, self-luminous, high contrast, long service life, and high photoelectric efficiency.

[0003] In the Micro-LED industry technology, millions or even tens of millions of LED (Light-Emitting Diode) chips need to be transferred from a growth substrate to a driving backplane through one or more times. In the traditional chip transfer scheme, when the chip is transferred from the growth substrate, the transfer precision is not high, and deviation is prone to occur, resulting in yield loss.

[0004] Therefore, how to improve the chip transfer precision in the chip transfer process is a problem to be solved. SUMMARY

[0005] In view of the above problems of the related art, the purpose of the present application is to provide a chip transfer method and a display panel, which aims to solve the problem of low transfer precision when the chip is transferred from the growth substrate.

[0006] A chip transfer method comprises the following steps:

[0007] A chip carrier plate is provided, and one side of the chip carrier plate is provided with a chip;

[0008] A temporary bonding structure is formed, which comprises a bonding layer arranged on the chip and a through hole arranged on the chip carrier plate, and the bonding layer is connected with the inner wall of the through hole;

[0009] The buffer layer connected with the chip carrier plate on the chip is removed, and the bonding layer makes the chip remain on the chip carrier plate;

[0010] The positions of the target substrate and the chip carrier plate are set so that the side of the chip carrier plate provided with the chip is opposite to the side of the target substrate for arranging the chip;

[0011] The bonding layer arranged on the chip to be transferred is disconnected with the through hole, so that the chip to be transferred is separated from the chip carrier plate and falls to the target substrate.

[0012] The chip transfer method sets an additional adhesive layer between the chip and the chip carrier through the temporary adhesive structure to realize the connection of the two, and removes the buffer layer connecting the chip and the chip carrier when transferring the chip, so that the chip and the chip carrier are combined only through the adhesive layer. Thus, the impact of the gas generated when the chip is peeled off by directly removing the buffer layer on the chip is avoided, and the chip is not skewed or offset, etc. The stability of the chip when the chip is peeled off from the chip carrier is improved, thereby ensuring the accuracy of the chip transfer. And due to the setting of the through hole, even if the adhesive layer generates gas during the process of disconnecting with the through hole, the gas is easy to be discharged along the direction of the through hole, that is, the direction of the gas impact can be controlled to a certain extent, ensuring that the chip is stable and accurately falls on the target carrier.

[0013] Optionally, the forming of the temporary adhesive structure comprises:

[0014] The region of the chip carrier where the chip is arranged forms the through hole;

[0015] The adhesive layer is formed on the chip and connected with the inner wall of the through hole.

[0016] Optionally, the forming of the through hole in the region of the chip carrier where the chip is arranged comprises:

[0017] A photoresist layer is arranged on the side of the chip carrier where the chip is not arranged;

[0018] The photoresist layer is subjected to a patterning process, so that the photoresist layer forms a temporary through hole corresponding to the position of the chip;

[0019] The chip carrier is etched using the photoresist layer as a mask, so that the region of the chip carrier corresponding to the temporary through hole is removed to form the through hole.

[0020] Optionally, the forming of the adhesive layer on the chip and connected with the inner wall of the through hole comprises:

[0021] The buffer layer of the region of the chip corresponding to the through hole is removed;

[0022] The adhesive layer is arranged on the region of the chip corresponding to the through hole.

[0023] Optionally, the adhesive layer is decomposed into gas after being irradiated by laser of a predetermined wave band;

[0024] The removing of the buffer layer of the chip connected with the chip carrier comprises:

[0025] The buffer layer is irradiated by laser of a wave band other than the predetermined wave band to decompose the buffer layer;

[0026] The method for transferring the chip includes:

[0027] The adhesive layer is irradiated by the laser of the predetermined wave band to decompose the adhesive layer.

[0028] Optionally, the method further includes:

[0029] The distance between the chip on the chip carrier and the target substrate is less than the length of the chip.

[0030] Optionally, the target substrate is provided with a die bonding area.

[0031] The method further includes:

[0032] The electrode of the chip on the chip carrier is aligned with the bonding area of the die bonding area.

[0033] After the chip to be transferred falls onto the target substrate, the method further includes:

[0034] The chip falling onto the target substrate is bonded with the target substrate.

[0035] It can be understood that in some embodiments, the chip transfer method can realize the chip transfer from the growth substrate of the chip to the circuit substrate, reduce the number of chip transfer, avoid the precision reduction caused by multiple transfers, and further ensure the high-precision transfer of the chip.

[0036] Optionally, before the chip to be transferred is separated from the chip carrier and falls onto the target substrate, the method further includes:

[0037] An anisotropic conductive adhesive layer is arranged on the side of the target substrate provided with the die bonding area.

[0038] The method of bonding the chip with the target substrate includes:

[0039] The chip adhered to the anisotropic conductive adhesive layer is electrically connected with the anisotropic conductive adhesive layer, and the anisotropic conductive adhesive layer limits the flow direction of the current to flow along the thickness direction of the anisotropic conductive adhesive layer.

[0040] It can be understood that by arranging the anisotropic conductive adhesive layer, the chip falling onto the target substrate is preliminarily bonded, which is beneficial to the stability of the chip after falling to a certain extent, avoids the deviation of the chip when falling onto the target substrate, and ensures the transfer precision.

[0041] Optionally, before the temporary bonding structure is formed, the method further includes:

[0042] Thinning the chip carrier to reduce the thickness of the chip carrier.

[0043] It can be understood that the thinner chip carrier is more prone to form the through hole of the temporary bonding structure in the above chip transfer process.

[0044] Based on the same inventive concept, the application also provides a display panel, comprising a light emitting chip and a circuit substrate, wherein the light emitting chip is transferred to the die bonding area of the circuit substrate by the chip transfer method of the above examples.

[0045] The light emitting chip of the display panel has high setting accuracy and good quality. In some implementation processes, the light emitting chip of the display panel of the embodiment can be directly transferred from the growth substrate to the circuit substrate, the number of transfer times is small, the influence on the yield of the light emitting chip is low, at the same time, the fewer transfer times also ensure the accuracy of chip transfer. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The basic flowchart of the chip transfer method provided by the embodiment of the application is shown in the figure;

[0047] Figure 2 The structure diagram after forming the temporary bonding structure provided by the embodiment of the application is shown in the figure;

[0048] Figure 3 The structure diagram of the chip on the chip carrier provided by the embodiment of the application is shown in the figure;

[0049] Figure 4 Another structure diagram after forming the temporary bonding structure provided by the embodiment of the application is shown in the figure;

[0050] Figure 5 The structure diagram after removing the buffer layer provided by the embodiment of the application is shown in the figure;

[0051] Figure 6 The structure diagram after removing the buffer layer of the structure is shown in the figure; Figure 4

[0052] Figure 7 The setting position diagram of the target substrate and the chip carrier provided by the embodiment of the application is shown in the figure;

[0053] Figure 8 Another structure diagram after forming the temporary bonding structure provided by the embodiment of the application is shown in the figure;

[0054] Figure 9 The basic flowchart of forming the temporary bonding structure provided by the embodiment of the application is shown in the figure;

[0055] Figure 10 ​A flowchart for forming a via hole according to an embodiment of the present application is shown in FIG. 1;

[0056] Figure 11 A schematic diagram for exposing a photoresist layer according to an embodiment of the present application is shown in FIG. 2;

[0057] Figure 12 A schematic diagram for patterning a photoresist layer according to an embodiment of the present application is shown in FIG. 3; Figure 11

[0058] Figure 13 A schematic diagram for etching a via hole according to an embodiment of the present application is shown in FIG. 4; Figure 12

[0059] A flowchart for forming an adhesive layer on a chip and connecting the adhesive layer to an inner wall of a via hole according to an embodiment of the present application is shown in FIG. 5; Figure 14

[0060] A schematic diagram for removing a buffer layer on a chip corresponding to a region of a via hole according to an embodiment of the present application is shown in FIG. 6; Figure 15

[0061] A schematic diagram for disposing an adhesive layer on a chip corresponding to a region of a via hole according to an embodiment of the present application is shown in FIG. 7; Figure 16

[0062] A schematic diagram for removing a buffer layer by using a laser according to an embodiment of the present application is shown in FIG. 8; Figure 17

[0063] A schematic diagram for disposing a distance between a chip and a target substrate on a chip carrier according to an embodiment of the present application is shown in FIG. 9; Figure 18

[0064] A schematic diagram for transferring a chip directly to a circuit substrate according to an embodiment of the present application is shown in FIG. 10; Figure 19

[0065] A schematic diagram for disposing an anisotropic conductive adhesive layer on a target substrate according to an embodiment of the present application is shown in FIG. 11; Figure 20 Legend of reference numerals:

[0066] 1-chip; 11-buffer layer; 12-other epitaxial layer; 121-N-type semiconductor layer; 122-active layer; 123-P-type semiconductor layer; 13-electrode; 2-adhesive layer; 3-chip carrier; 4-via hole; 5-target substrate; 51-circuit substrate; 52-pad; 53-anisotropic conductive adhesive layer; 6-photoresist layer; 61-temporary via hole; 7-mask.

[0067] DETAILED DESCRIPTION

[0068] ​​For the purposes of this application, a more complete description of the application will be presented in the following with reference to the accompanying drawings. The drawings show the preferred embodiments of the application. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the application more thorough and comprehensive.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the specification of the application herein is only for the purpose of describing specific embodiments and is not intended to limit the application.

[0070] During the process of chip transfer, there is a problem of low chip transfer accuracy. Based on this, the present application hopes to provide a solution to the above technical problem, the details of which will be described in the subsequent embodiments.

[0071] Embodiments:

[0072] The present embodiment provides a chip transfer method, please refer to Figure 1 , the chip transfer method comprises:

[0073] S101, providing a chip carrier plate, one side of the chip carrier plate is provided with a chip;

[0074] S102, forming a temporary bonding structure;

[0075] It should be noted that, please refer to Figure 2 , the temporary bonding structure of the present embodiment includes an adhesive layer 2 disposed on the chip 1, and a through hole 4 disposed on the chip carrier plate 3, the adhesive layer 2 is connected with the inner wall of the through hole 4. In some examples, the through hole exposes the part of the chip close to the side of the chip carrier plate, and the adhesive layer is disposed on the exposed area of the chip. It can be understood that the adhesive layer has certain adhesion, which can be connected with the chip and the inner wall of the through hole through adhesion.

[0076] The chip in the present embodiment includes but is not limited to LED light-emitting chip or other any chip that needs to be transferred. Exemplarily, the LED light-emitting chip includes but is not limited to Mini-LED (Mini Light-Emitting Diode, Mini Light-Emitting Diode) chip, Micro-LED, etc., for example, in one example, the LED chip can be a Mini-LED chip; in another example, the LED chip can be a Micro-LED chip.

[0077] In Figure 2In this example, chip 1 includes an epitaxial layer grown on a chip substrate 3. The epitaxial layer includes a buffer layer 11 and other epitaxial layers 12, with the buffer layer 11 in contact with the chip substrate 3. When forming a temporary bonding structure, the buffer layer 11 corresponding to the via 4 on chip 1 is removed, and an adhesive layer 2 is disposed on the other epitaxial layers 12 of chip 1. In this example, the thickness of the adhesive layer 2 is greater than that of the buffer layer 11 to ensure that the adhesive layer 2 can contact the via 4 on the chip substrate 3.

[0078] As a concrete example, see Figure 3 Chip 1 is a Micro-LED chip, grown on a chip carrier 3. The Micro-LED chip on the chip carrier 3 includes an epitaxial layer and an electrode 13. The epitaxial layer sequentially includes a buffer layer 11 and other epitaxial layers 12. Exemplarily, the other epitaxial layers 12 include, but are not limited to, an N-type semiconductor layer 121, an active layer 122, and a P-type semiconductor layer 123. The active layer 122 may include a quantum well layer, and may also include other structures. In some other examples, the epitaxial layer may optionally include at least one of a reflective layer and a passivation layer. The material and shape of the electrode 13 are not limited. For example, in one example, the material of the electrode 13 may include, but is not limited to, at least one of Cr, Ni, Al, Ti, Au, Pt, W, Pb, Rh, Sn, Cu, and Ag.

[0079] In other examples, such as Figure 4 As shown, when forming a temporary bonding structure, the buffer layer 11 of chip 1 can be completely retained, and the bonding layer 2 can be disposed on the portion of the buffer layer 11 of chip 1 corresponding to the via 4. In this example, the remaining buffer layer 11 on chip 1 can be removed after chip 1 is transferred to the target substrate.

[0080] S103. Remove the buffer layer on the chip that is connected to the chip carrier, and the adhesive layer keeps the chip on the chip carrier.

[0081] like Figure 5 As shown, in this embodiment, the buffer layer connecting chip 1 to the chip carrier 3 is removed. At this point, chip 1, except for the adhesive layer 2, has no other connection to the chip carrier 3. Because the adhesive layer 2 is connected to the inner wall of the through-hole 4, chip 1 can remain on the chip carrier 3 without detaching from it due to the adhesiveness of the adhesive layer 2. Based on... Figure 4 As shown in the example, after removing the buffer layer on chip 1 that connects to chip carrier 3, as... Figure 6 As shown, the portion of the buffer layer 11 with the adhesive layer 2 is not removed because it is no longer connected to the chip carrier 3, while the remaining portion of the buffer layer 11 is removed.

[0082] S104, positions of the target substrate and the chip carrier are set so that the side of the chip carrier provided with the chip is opposite to the side of the target substrate for setting the chip;

[0083] For example, as shown in FIG. 1, the positions of the target substrate 5 and the chip carrier 3 are set to be opposite to each other. In some examples, the target substrate 5 and the chip carrier 3 can be opposite to each other in the vertical direction, and the chip 1 on the chip carrier 3 can fall vertically under the action of gravity after being separated from the chip carrier 3. Figure 7

[0084] S105, the adhesive layer provided on the chip to be transferred is disconnected from the through hole, so that the chip to be transferred is separated from the chip carrier;

[0085] The chip falls on the target substrate after being separated from the chip carrier, realizing the transfer from the chip carrier to the target substrate.

[0086] It can be understood that after the transfer of the chip is completed, if the adhesive layer and / or the buffer layer remain on the chip, the remaining adhesive layer and / or the buffer layer can be removed in the subsequent process.

[0087] In this embodiment, an additional adhesive layer is provided between the chip and the chip carrier through the temporary adhesive structure to realize the connection of the two, and when the chip is transferred, the buffer layer connecting the chip and the chip carrier is removed, so that the chip and the chip carrier are combined only through the adhesive layer. Thus, the impact of the gas generated when the chip is peeled off by directly removing the buffer layer on the chip is avoided, and the chip is not offset, and the stability of the chip when the chip is peeled off from the chip carrier is improved, thereby ensuring the accuracy of the chip transfer. Moreover, due to the provision of the through hole, even if the adhesive layer generates gas during the process of disconnecting from the through hole, the gas is easily discharged along the direction of the through hole, that is, the direction of the gas impact can be controlled to some extent, ensuring that the chip falls stably and accurately on the target substrate.

[0088] The chip carrier of this embodiment can be a growth substrate for growing a chip. The chip transfer method of this embodiment accurately transfers the chip on the chip carrier to the target substrate. The target substrate can be any substrate for receiving a chip, including but not limited to a temporary storage substrate for temporarily storing a chip, a transfer substrate for picking up and transferring a chip, a circuit substrate for setting a chip to realize a corresponding function, etc.

[0089] It can be understood that the chip carrier can be any material for growing a chip, including but not limited to sapphire, silicon carbide, silicon, gallium arsenide, and other semiconductor materials.

[0090] ​The shape of the through hole can be any shape, for example, the cross section of the through hole can be circular, oval, polygonal, etc. The number of through holes is not limited for a single chip, for example, when one through hole is formed corresponding to a single chip, the through hole can be arranged in the central region of the chip. In another example, referring to Figure 8 , the chip carrier 3 is provided with two through holes 4 in the region corresponding to a single chip 1, the two through holes 4 are arranged symmetrically corresponding to the two sides of the chip 1, and the chip 1 is provided with an adhesive layer 2 corresponding to the region of the two through holes 4 respectively.

[0091] Referring to Figure 9 , in some embodiments, a temporary adhesive structure is formed, including:

[0092] S201, forming a through hole in the region of the chip carrier where the chip is arranged;

[0093] In one example, the through hole extends along the thickness direction of the chip carrier, the cross-sectional area of the through hole is smaller than the area of the chip in contact with the chip carrier, and the through hole exposes a part of the epitaxial layer of the chip.

[0094] S202, forming an adhesive layer on the chip connected to the inner wall of the through hole;

[0095] That is, in some embodiments, the through hole is formed first, and then the adhesive layer is arranged.

[0096] Referring to Figure 10 , in some embodiments, a through hole is formed in the region of the chip carrier where the chip is arranged, including:

[0097] S2011, arranging a photoresist layer on the side of the chip carrier where the chip is not arranged;

[0098] S2012, patterning the photoresist layer to form a temporary through hole in the position corresponding to the chip of the photoresist layer;

[0099] Referring to Figure 11 , the photoresist layer 6 is exposed using a mask plate 7, in this example, the photoresist layer 6 can be selected as a positive photoresist, it can be understood that in other examples, a negative photoresist can be selected. As shown in Figure 12 , the exposed photoresist layer 6 is developed, and a temporary through hole 61 is formed on the photoresist layer 6.

[0100] S2013, using the photoresist layer as a mask plate to etch the chip carrier, so that the region of the chip carrier corresponding to the temporary through hole is removed to form a through hole;

[0101] As shown in Figure 13As shown, a portion of the chip carrier 3 is removed to form a via 4. In an example, the etching of the chip carrier can employ, but is not limited to, dry etching, such as reactive ion etching (RIE), inductively coupled plasma (ICP) etching, etc.

[0102] Referring to Figure 14 In some embodiments, forming an adhesive layer on the chip to connect with the inner wall of the via includes:

[0103] S2021, removing the buffer layer on the chip corresponding to the region of the via;

[0104] As Figure 15 In this step, only the buffer layer 11 on the chip 1 corresponding to the region of the via 4 is removed, while the buffer layer 11 on the chip 1 connected with the chip carrier 3 is still reserved. At this time, the chip 1 is connected with the chip carrier 3 through the remaining buffer layer 11, which ensures that the chip 1 does not separate from the chip carrier 3. In this process, the removal of the buffer layer can be achieved by means including, but not limited to, laser or etching, etc.

[0105] In an example, the photoresist layer used as a mask in the process of forming the via as described in Figure 15 is temporarily reserved after the via is formed. In this step S2021 of removing the buffer layer, the photoresist layer is also used as a mask to selectively remove the buffer layer corresponding to the region of the via. After the photoresist layer is used, it can be removed.

[0106] S2022, setting an adhesive layer on the chip corresponding to the region of the via;

[0107] Referring to Figure 16 Since the buffer layer has a certain thickness, the adhesive layer set in this example is higher than the thickness of the buffer layer, so as to be connected with the inner wall of the via.

[0108] In this embodiment, the adhesive layer can be a material that can be released from adhesion under certain conditions, or a material that can be decomposed under certain conditions. By releasing the adhesion of the adhesive layer or decomposing it, the adhesive layer can be released from the connection with the via.

[0109] For example, in some embodiments, the adhesive layer is decomposed into a gas after being irradiated by a laser of a predetermined waveband. The method of removing the buffer layer on the chip connected with the chip carrier can include: irradiating the buffer layer with a laser of a waveband other than the predetermined waveband to decompose the buffer layer, that is, the adhesive layer is not affected when the buffer layer is decomposed. The method of releasing the adhesive layer set on the chip to be transferred from the connection with the via includes: irradiating the adhesive layer with a laser of the predetermined waveband to decompose the adhesive layer. In an example, refer to Figure 17The laser of the wave band other than the predetermined wave band is irradiated to the buffer layer through the side of the chip carrier board where the chip is not arranged, and the chip is connected to the chip carrier board only through the adhesive layer after the buffer layer is decomposed. In this embodiment, the adhesive layer is decomposed to generate gas, and it can be understood that part of the gas generated by the decomposition of the adhesive layer can be discharged through the through hole, reducing the impact on the chip and the direction of the gas discharge being controlled by the through hole. In some implementation processes, the through hole is directly opposite the target carrier board, so that the gas generated by the decomposition of the adhesive layer can also generate a force towards the target carrier board on the chip, and the impact direction of the force is accurate. Through the cooperation of the through hole and the adhesive layer, the chip can be accurately dropped onto the target carrier board while facilitating the separation of the chip from the chip carrier board.

[0110] As a specific example, the adhesive layer includes but is not limited to a glue material of polymethyl methacrylate (PMMA), polyimide (PI), and other polymers, and such an adhesive layer can be arranged through processes including but not limited to spin coating, spraying, and the like. For the adhesive layer formed of such polymers, the preset wave band of the laser can include 355 nm, 532 nm, 1064 nm, and the like, which are different from the wave band of the laser usually used in the decomposition of the buffer layer.

[0111] For example, the material of the buffer layer includes but is not limited to gallium nitride (GaN), which can be decomposed into nitrogen and gallium at a certain temperature. In actual applications, the gallium nitride can be irradiated by a laser of a certain wave band to generate heat and warm up to a predetermined temperature to decompose. In this embodiment, a laser of a wave band other than the preset wave band and capable of decomposing gallium nitride is used to irradiate the gallium nitride material buffer layer, for example, a laser of 248 nm wave band, which is different from the preset wave band for decomposing the adhesive layer. In other examples, a wave band other than the preset wave band for decomposing the adhesive layer can also be selected.

[0112] In some embodiments, before the temporary adhesive structure is formed, the chip carrier board is thinned to reduce the thickness of the chip carrier board. The formation of the temporary adhesive structure requires the formation of a through hole structure on the chip carrier board, which is equivalent to removing part of the material on the chip carrier board. A thinner chip carrier board is easier to form a temporary adhesive structure. In the process of etching, for example, to remove part of the material on the chip carrier board, the depth of etching is reduced, saving time and reducing the difficulty of the process.

[0113] To further ensure the accuracy of the chip during the transfer process, the distance between the target substrate and the chip carrier can be adjusted. In some embodiments, a shorter distance between the target substrate and the chip carrier can reduce the degree of possible deviation of the chip to some extent. Therefore, in some examples, the step S103 of setting the position of the target substrate and the chip carrier further includes:

[0114] S1031, the distance between the chip on the chip carrier and the target substrate is less than the length of the chip.

[0115] As Figure 18 , the distance between the chip 1 on the chip carrier 3 and the target substrate 5 is selected according to the length of the formed chip. It should be noted that in this embodiment, the length of the chip is the length of the longer side, and in this example, the length of the chip is h1. When setting the position of the target substrate 5 and the chip carrier 3, the distance between the chip 1 and the target substrate 5 is h2, where h1 is greater than h2.

[0116] In some embodiments, the target substrate is provided with a die bonding area; and setting the position of the target substrate and the chip carrier further includes aligning the electrodes of the chip on the chip carrier with the bonding area of the die bonding area, which includes but is not limited to the area of the pads. In these embodiments, the target substrate can be various circuit substrates, such as a driving backplane of a light-emitting chip, etc. After the chip to be transferred falls onto the target substrate, it further includes bonding the chip that falls onto the target substrate with the target substrate. In an example, as Figure 19 , the target substrate is a circuit substrate 51 provided with pads, which can be provided with a driving circuit to drive and control the chip 1, and the electrodes 13 of the chip are aligned with the pads 52 of the circuit substrate 51, and are directly transferred from the chip carrier 3 on which the chip is grown to the circuit substrate 51 without going through an intermediate transfer process. That is, the chip transfer method of this embodiment can realize direct transfer, and the chip carrier 3 and the circuit substrate 51 do not need to be in contact, which is conducive to the selective transfer of the chip 1. The bonding of the chip 1 and the circuit substrate 51 includes welding the electrodes 13 of the chip 1 with the pads 52. By directly transferring the chip grown on the chip carrier to the target substrate such as a circuit substrate, the intermediate transfer steps are omitted, the number of transfers is reduced, the impact on the yield of the chip is smaller, and fewer transfer times further ensure the accuracy of the chip transfer.

[0117] To better ensure the accuracy of the chip transferred to the target substrate, in some embodiments, a certain adhesive layer can be provided on the target substrate. After the chip falls onto the target substrate, it is adhered by the adhesive layer with a certain adhesion, so that the chip and the target substrate are preliminarily combined to avoid deviation of the chip when falling onto the target substrate.

[0118] The target substrate provided with the die bonding area based on the foregoing example, before the chip to be transferred is separated from the chip carrier board and falls on the target substrate, further comprises: setting an anisotropic conductive adhesive layer on the side of the target substrate provided with the die bonding area;

[0119] Bonding the chip with the target substrate, comprising: electrically connecting the chip adhered to the anisotropic conductive adhesive layer with the anisotropic conductive adhesive layer, and the anisotropic conductive adhesive layer limits the flowing direction of the current to flow along the thickness direction of the anisotropic conductive adhesive layer.

[0120] For example, referring to Figure 20 As shown in the figure, the target substrate 5 is provided with a pad 52, which is used as a bonding area to realize electrical connection with the chip 1. Before the chip 1 is separated from the chip carrier board 3, an anisotropic conductive adhesive layer 53 is coated on the side of the target substrate 5 provided with the pad 52, and the thickness of the anisotropic conductive adhesive layer 53 is greater than the height of the pad 52, that is, the anisotropic conductive adhesive layer 53 completely covers the pad 52. When the positions of the target substrate 5 and the chip carrier board 3 are set, the electrodes of the chip 1 on the chip carrier board 3 are aligned with the pad 52 of the target substrate, and after the chip 1 falls on the target substrate 5, the electrodes of the chip 1 are not in direct contact with the pad 52, but are bonded with the anisotropic conductive adhesive layer 53, but the electrodes of the chip 1 are opposite to the position of the pad 52, and the anisotropic conductive adhesive layer 53 conducts current in the thickness direction, so that the electrodes of the chip 1 can have an electrical connection relationship with the pad 52.

[0121] By setting the anisotropic conductive adhesive layer, the chip can be initially bonded to the target substrate when falling on the target substrate, and the anisotropic conductive adhesive layer can be directly used to bond the chip with the target substrate.

[0122] Of course, in other examples, for example, the target substrate is a temporary substrate, and only needs to temporarily store the chip, and no die bonding area is provided, so a general adhesive layer can be used to initially bond the chip.

[0123] In actual application, the chip transfer method of the embodiment can be non-selective transfer or selective transfer, that is, all chips on the chip carrier board can be transferred, or part of the chips on the chip carrier board can be selectively transferred. It can be understood that selective transfer can be performed only by selectively disconnecting the bonding layer from the through hole. For example, a laser of a predetermined wave band is used to selectively irradiate the bonding layer of part of the chips that need to be transferred, so that only the part of the chips that need to be transferred are separated from the chip carrier board, thereby realizing selective transfer.

[0124] The embodiment also provides a display panel, which comprises a light emitting chip and a circuit substrate, and the light emitting chip is transferred to a die bonding area of the circuit substrate by the chip transfer method described above. The display panel has high setting precision and good quality. In some implementation processes, the light emitting chip of the display panel can be directly transferred from a growth substrate to the circuit substrate, the number of transfer times is small, the influence on the yield of the light emitting chip is low, at the same time, the number of transfer times is small, and the precision of chip transfer is also ensured.

[0125] It should be understood that the application is not limited to the above examples, and can be improved or changed according to the above description for those skilled in the art, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. A chip transfer method characterized by, The application relates to a chip transfer method, which comprises the following steps: providing a chip carrier plate, one side of which is provided with a chip; forming a temporary bonding structure, which comprises a bonding layer arranged on the chip and a through hole arranged on the chip carrier plate, the bonding layer being connected with the inner wall of the through hole; removing the buffer layer on the chip connected with the chip carrier plate, the bonding layer keeping the chip on the chip carrier plate; arranging the position of a target substrate and the chip carrier plate so that the side of the chip carrier plate provided with the chip is opposite to the side of the target substrate for arranging the chip; disconnecting the bonding layer arranged on the chip to be transferred from the through hole so that the chip to be transferred is separated from the chip carrier plate and falls on the target substrate.

2. The chip transfer method according to claim 1, wherein The forming of the temporary bonding structure comprises: forming the through hole on the region of the chip carrier plate provided with the chip; forming the bonding layer connected with the inner wall of the through hole on the chip.

3. The chip transfer method according to claim 2, wherein The forming of the through hole on the region of the chip carrier plate provided with the chip comprises: arranging a photoresist layer on the side of the chip carrier plate not provided with the chip; performing a patterning treatment on the photoresist layer so that the photoresist layer forms a temporary through hole corresponding to the position of the chip; etching the chip carrier plate by using the photoresist layer as a mask plate, so that the region of the chip carrier plate corresponding to the temporary through hole is removed to form the through hole.

4. The chip transfer method according to claim 2, wherein The forming of the bonding layer connected with the inner wall of the through hole on the chip comprises: removing the buffer layer on the region of the chip corresponding to the through hole; arranging the bonding layer on the region of the chip corresponding to the through hole.

5. The chip transfer method according to claim 1, wherein The bonding layer is decomposed into gas after being irradiated by laser of a predetermined wave band; The removing of the buffer layer on the chip connected with the chip carrier plate comprises: irradiating the buffer layer by laser of a wave band other than the predetermined wave band to decompose the buffer layer; The disconnecting of the bonding layer arranged on the chip to be transferred from the through hole comprises: irradiating the bonding layer by laser of the predetermined wave band to decompose the bonding layer.

6. The chip transfer method according to claim 1, wherein The arrangement of the position of the target substrate and the chip carrier plate further comprises: making the distance between the chip on the chip carrier plate and the target substrate less than the length of the chip.

7. The method of claim 1-6, wherein, The target substrate is provided with a die bonding area; The arrangement of the position of the target substrate and the chip carrier plate further comprises: aligning the electrode of the chip on the chip carrier plate with the bonding area of the die bonding area; After the chip to be transferred falls on the target substrate, the chip on the target substrate is further bonded with the target substrate. Before the chip to be transferred is separated from the chip carrier plate and falls on the target substrate, the method further comprises:

8. The chip transfer method according to claim 7, wherein arranging an anisotropic conductive adhesive layer on the side of the target substrate provided with the die bonding area; The bonding of the chip and the target substrate comprises: making the chip adhered to the anisotropic conductive adhesive layer electrically connected with the anisotropic conductive adhesive layer, the anisotropic conductive adhesive layer limiting the flowing direction of the current to be along the thickness direction of the anisotropic conductive adhesive layer. ​ 9. The method of claim 1-6, wherein, Before the forming of the temporary adhesive structure, further comprising: Thinning the chip carrier to reduce the thickness of the chip carrier.

10. A display panel, characterized by, The display panel comprises light emitting chips and a circuit substrate, and the light emitting chips are transferred to the die bonding area of the circuit substrate by the chip transfer method according to any one of claims 1-9.

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