Chip bonding method, display panel and display device

Abstract

The invention discloses a chip bonding method, a display panel and a display device, and the method comprises the steps: providing a backboard which is provided with a plurality of holes which are not conducted, and the whole layer of the backboard is coated with an adhesive solution; a light-emitting chip is transferred to the surface, provided with the bonding glue solution, of the back plate; the back plate is heated so that the multiple holes can be communicated, the adhesive liquid flows out of the multiple holes to drive the light-emitting chip to move in the direction close to the back plate, and bonding of the light-emitting chip and the back plate is achieved. The problem that the production cost of the whole display panel is high due to the fact that special equipment and process conditions are needed in a mode of pressing eutectic bonding in a high-temperature and high-pressure environment in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of display device manufacturing, and in particular to a chip bonding method, a display panel, and a display device. Background Art

[0002] In the current Micro-LED display technology, one of the main bottlenecks in the production process of Micro-LED display panels lies in mass transfer. In the mass transfer technology, currently, almost all the bonding methods in the process of Micro-LED chip transfer use the pressure eutectic bonding method. In the specific implementation process of this method, pressure needs to be applied to the Micro-LED chip under high temperature and high pressure conditions, so as to press and eutectically bond the electrodes of the Micro-LED chip with the electrodes of the backplane.

[0003] However, the existing method of pressure eutectic bonding using a high temperature and high pressure environment requires special equipment and process conditions. Usually, the cost of equipment and processes that can meet the special high temperature and high pressure environment is relatively high, resulting in a high production cost and high price of the entire display panel.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above deficiencies of the prior art, the purpose of the present application is to provide a chip bonding method, a display panel, and a display device, so as to solve the problem that the existing method of pressure eutectic bonding using a high temperature and high pressure environment requires special equipment and process conditions, resulting in a high production cost of the entire display panel.

[0006] The technical solution of the present application is as follows:

[0007] On the one hand, the present application proposes a chip bonding method, including the steps of:

[0008] Providing a backplane, on which a plurality of unconducted holes are provided, and the entire layer of the backplane is coated with an adhesive liquid;

[0009] Transferring a light-emitting chip to the surface of the backplane provided with the adhesive liquid;

[0010] Heating the backplane to make the plurality of holes conductive, and the adhesive liquid flows out from the plurality of holes to drive the light-emitting chip to move towards the backplane, realizing bonding with the backplane.

[0011] Through the above scheme, a blocked and unconducted hole is opened on the back panel. When the entire layer of the back panel is coated with adhesive, the adhesive will not flow out from the surface of the back panel. After a direct transfer process, the light-emitting chip is set on the surface of the back panel, and then heated. The holes on the back panel are opened and turned on by heating, so that the adhesive flows toward the holes, and the thickness of the adhesive on the back panel becomes thinner, thereby driving the light-emitting chip to move down and gradually approach the surface of the back panel. Finally, the electrode of the light-emitting chip contacts the electrode of the back panel under the action of the adsorption force in the hole, and eutectic bonding is achieved at the heated temperature. In this process, eutectic bonding does not need to be performed under high pressure, which makes the production process more optimized and the production equipment used simpler.

[0012] Optionally, providing a back plate, wherein a plurality of non-conducting holes are provided on the back plate, comprises:

[0013] A back plate is provided, wherein a plurality of non-conductive holes are arranged at the middle position of the back plate and at the edge positions on both sides relative to the middle position, wherein the size of the holes at the middle position is smaller than the size of the holes at the edge positions on both sides.

[0014] According to the above scheme, the holes at the edge have a large aperture, which can flow out a large amount of diluent in the adhesive glue, thereby increasing the outflow speed of the diluent in the adhesive glue. The holes at the middle position have a small aperture, which can not only flow out the diluent in the adhesive glue, but also adsorb the light-emitting chip. The aperture of the hole at the middle position is set to be relatively small, so that the loss of the adhesive glue is very limited, and the middle position of the backplane is used to bond the light-emitting chip, so as to ensure that there is enough glue in the fixing area of ​​the light-emitting chip to fix the light-emitting chip.

[0015] Optionally, the plurality of non-conducting holes are filled with heated molten material, and the heated molten material is in a flowing state under heating conditions, so that the plurality of holes are transformed from a non-conducting state to a conducting state.

[0016] According to the above scheme, the holes are sealed by the heated molten material, and when the holes are opened, the heating environment of the eutectic bonding can be directly used to open the holes, thereby optimizing the hole opening process.

[0017] Optionally, the heated fusible material comprises hot melt adhesive.

[0018] Through the above scheme, the hot melt adhesive can be directly applied by dispensing in the process of plugging holes. The process is simple and the dispensing position is accurate, which greatly reduces the difficulty of plugging holes.

[0019] Optionally, the step of heating the backplane to make the multiple holes conductive and causing the adhesive to flow out of the multiple holes to drive the light-emitting chip to move toward the backplane further includes:

[0020] Heat the backplane so that the adhesive liquid evaporates and the light-emitting chip moves towards the backplane.

[0021] Through the above solution, the adhesive liquid not only flows out through the glue outlet holes, but also evaporates in a heating environment, thereby accelerating the thinning speed of the adhesive liquid and improving the transfer efficiency.

[0022] Optionally, in the step of heating the backplane to make multiple holes conduct and the adhesive liquid flows out from the multiple holes to drive the light-emitting chip to move towards the backplane, it further includes:

[0023] Apply negative pressure adsorption to the light-emitting chip to make the light-emitting chip move towards the backplane and contact for eutectic bonding.

[0024] Through the above solution, the negative pressure adsorption mechanism sends the backplane with the light-emitting chip into the heating chamber, while performing negative pressure adsorption and heating. The heating and negative pressure adsorption make the outflow speed of the diluent faster, and the negative pressure adsorption of the light-emitting chip makes the moving speed of the light-emitting chip towards the backplane faster, thereby improving the connection speed between the light-emitting chip and the backplane. Moreover, during the process of the adhesive liquid gradually thinning, it is slower than the process of directly extruding through high pressure, so that the bubbles at the bonding interface can be slowly discharged, avoiding the problem that the bubbles cannot be discharged in time due to the use of high pressure.

[0025] On the other hand, based on the same concept, the present application also proposes a display panel, which includes: a backplane and a light-emitting chip;

[0026] Multiple holes are provided on the backplane, and the light-emitting chip is fixed on the backplane through an adhesive liquid;

[0027] During the eutectic bonding process between the light-emitting chip and the backplane, heat the backplane to convert multiple holes from a non-conducting state to a conducting state, so that the adhesive liquid flows out from the multiple holes to drive the light-emitting chip to move towards the backplane.

[0028] Through the above solution, during the production process of the display panel, the holes on the backplane play a role in reducing production costs. The holes are opened and conducted by heating, so that the adhesive liquid flows towards the holes, thinning the thickness of the adhesive liquid on the backplane, thereby driving the light-emitting chip to move downwards and gradually approach the surface of the backplane. Finally, the electrodes of the light-emitting chip contact the electrodes of the backplane under the action of the adsorption force in the holes and achieve eutectic bonding at the heating temperature. In this process, eutectic bonding does not need to be carried out in a high-pressure environment, optimizing the production process and making the production equipment used simpler.

[0029] Optionally, a plurality of the holes are disposed at the middle position of the backplane and the edge positions on both sides relative to the middle position; wherein, the size of the holes at the middle position is smaller than the size of the holes at the edge positions on both sides.

[0030] Through the above solution, by setting the holes at different positions on the backplane to different sizes, it can ensure that there is enough adhesive liquid in the fixed area of the light-emitting chip to fix the light-emitting chip, and the adhesive liquid in the fixed area of the non-light-emitting chip can flow and quickly drive the light-emitting chip to move down.

[0031] Optionally, the arrangement density of the holes at the middle position gradually increases in the direction close to the electrode of the backplane.

[0032] Through the above solution, the alignment between the electrode of the light-emitting chip and the electrode of the backplane is more accurate, and the connection is more stable after the electrode eutectic bonding.

[0033] In a third aspect, based on the same concept, the present application also proposes a display device, which includes the display panel as described above.

[0034] Through the above solution, the production process of the display device is simpler and the production cost is lower.

[0035] The beneficial effect of the present application is that: an openable hole is formed on the backplane, an adhesive liquid is coated on the backplane and a light-emitting chip is placed, and the backplane is moved into a heating chamber. During heating, the hole is opened, so that part of the adhesive liquid flows out and becomes thinner. After the light-emitting chip moves down, eutectic bonding without pressing is achieved between the light-emitting chip and the electrode of the backplane. The transfer process is optimized, the equipment requirements are reduced, the production cost is reduced, and the defect rate of the light-emitting chip during the transfer process is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a main process flow block diagram of a chip bonding method according to an embodiment of the present application;

[0037] Figure 2 It is a specific process flow block diagram of step S300 of a chip bonding method according to an embodiment of the present application;

[0038] Figure 3 It is a schematic structural diagram of a backplane in a chip bonding method according to an embodiment of the present application;

[0039] Figure 4 It is a schematic structural diagram of a structure for plugging holes on a backplane in a chip bonding method according to an embodiment of the present application;

[0040] Figure 5 It is a perspective structural diagram of coating an adhesive liquid on a backplane in a chip bonding method according to an embodiment of the present application;

[0041] Figure 6This is a perspective structural diagram of bonding a light-emitting chip to a backplane in a chip bonding method according to an embodiment of the present application;

[0042] Figure 7 This is a schematic diagram of the structure of a light-emitting chip after eutectic bonding in a chip bonding method according to an embodiment of the present application;

[0043] Figure 8 This is a schematic diagram of the principle of a transfer device according to an embodiment of the present application.

[0044] The numbers in the figure are: 10, back plate; 20, hole; 21, edge hole; 22, middle hole; 23, hot melt adhesive; 30, adhesive glue; 40, light-emitting chip; 50, direct rotation mechanism; 60, transmission mechanism; 70, negative pressure adsorption mechanism; 80, heating mechanism; 81, heating chamber. DETAILED DESCRIPTION

[0045] The present application provides a chip bonding method, a display panel, and a display device. To make the purpose, technical solution, and effect of the present application clearer and more specific, the present application is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] The existing method of using high temperature and high pressure environment for press eutectic bonding not only requires special equipment and process conditions, but also leads to high equipment and process costs. In addition, under the action of high pressure, there is a probability of uneven distribution of bonding materials, bubbles at the bonding interface, offset of the light-emitting chip, and poor pressure on the light-emitting chip, thereby affecting the transfer effect of the light-emitting chip. To solve the above problems, this application proposes the following implementation plan:

[0047] One implementation method is:

[0048] like Figure 7 As shown, this embodiment provides a chip bonding method for fixing the light emitting chip 40 on the back plate 10 to form a display panel. Figure 1 , Figure 2 As shown, the chip bonding method includes the following steps:

[0049] Step S50: Mix the receiving glue solution and the diluent to prepare the bonding glue solution.

[0050] like Figure 5 , Figure 6 , Figure 7As shown, during the specific process, the light-emitting chip 40 needs to be adhesively fixed to the backplane 10. The adhesive liquid 30 can be prepared in advance. The adhesive liquid 30 is composed of a receiving adhesive liquid and a diluent. The adhesive liquid 30 can be a glue with a viscosity of about 2400 cps, which has a high viscosity and can enable the light-emitting chip 40 to be normally adhered to the backplane 10 for fixation. The diluent can be n-heptane. The diluent and the receiving adhesive liquid are mixed so that the proportion of the receiving adhesive liquid in the mixed adhesive liquid 30 is small at first, so that it can be laid thicker on the backplane 10. In the subsequent process, the diluent is removed and the light-emitting chip 40 can slowly descend, and the proportion of the receiving adhesive liquid in the adhesive liquid 30 becomes larger and larger, so as to realize the stable adhesive fixation of the light-emitting chip 40.

[0051] In this embodiment, the mixing ratio of the receiving adhesive liquid to the diluent is that the receiving adhesive liquid:diluent = 1:2 - 1:10. Using the mixing ratio within this range makes the removal process of the diluent smoother in the subsequent process and ensures the stability of the bonding of the light-emitting chip.

[0052] The receiving adhesive liquid is the glue used in the bonding of the light-emitting chip. To ensure the adhesiveness, the receiving adhesive liquid has a high viscosity. And the adhesive liquid used in the process is the mixed glue after the receiving adhesive liquid is mixed with the diluent. Due to the dilution effect, the proportion of the receiving adhesive liquid component in the adhesive liquid decreases, the viscosity decreases and the fluidity increases. Therefore, the adhesive liquid may be sucked away during the negative pressure adsorption process. Therefore, by adding the diluent, the outflow of the diluent from the holes is accelerated, and the thinning speed of the adhesive liquid is increased until the receiving adhesive liquid is cured by heating, and more diluent flows out and the loss of the receiving adhesive liquid itself is less.

[0053] Step S100: Provide a backplane, on which a plurality of unconnected holes are provided, and the entire surface of the backplane is coated with an adhesive liquid.

[0054] As Figure 3 、 Figure 4 As shown, during the specific process, in order to prevent the adhesive liquid 30 from leaking out on the entire surface of the backplane 10, the holes 20 of the backplane 10 are blocked first. Thus, the front surface of the backplane 10 will not leak liquid, and the process of coating the entire surface of the front surface of the backplane 10 is simpler.

[0055] In this embodiment, the holes 20 are distributed on the surface of the backplane 10, and the heat-meltable material is filled between the plurality of unconnected holes 20. The heat-meltable material is in a flowing state under the heating condition, so that the plurality of holes are changed from the unconnected state to the connected state. By blocking the holes 20 with the heat-meltable material, when opening the holes 20, the holes can be directly opened by using the heating environment of the eutectic bonding, optimizing the opening process of the holes.

[0056] The heated molten material in this embodiment includes hot melt adhesive 23. The hot melt adhesive 23 blocks the hole. When heated, the hot melt adhesive 23 melts directly to open the hole 20. The glue coating method can be directly adopted. The process is simple and the glue dispensing position is accurate, which greatly reduces the difficulty of blocking the hole. In addition, with the cooperation of negative pressure suction, the melted hot melt adhesive 23 can be quickly separated from the hole 20. Not only does it not need to adopt other conditions to open the hole 20, making the process simpler; the hot melt adhesive 23 can fall off quickly, increasing the opening speed of the hole 20; thereby improving the efficiency of the entire transfer process.

[0057] like Figure 4 As shown, the holes 20 in this embodiment are specifically: a plurality of non-conductive holes are arranged at the middle position of the back plate and at the edge positions on both sides relative to the middle position, wherein the size of the hole at the middle position is smaller than the size of the hole at the edge positions on both sides. In the specific structure, three light-emitting chips are used as a group of light-emitting units, and the light-emitting chips in each light-emitting unit are arranged side by side in an arrangement direction, and the two ends of each light-emitting unit in the above arrangement direction are the edge positions of the back plate, and the area between the edge positions is the middle position.

[0058] The hole 20 arranged at the edge position is an edge hole 21, and the hole 20 at the middle position is an intermediate hole 22. The aperture of the intermediate hole 22 is smaller than the aperture of the edge hole 21. A plurality of edge holes 21 are arranged at the edge of the back plate 10, and a plurality of intermediate holes 22 are arranged within the area surrounded by the edge holes 21. The large aperture of the edge hole 21 allows a large amount of diluent to flow out, thereby increasing the outflow speed of the diluent. The aperture of the intermediate hole 22 is small, so that not only the diluent can flow out, but also the light-emitting chip 40 can be adsorbed. The aperture of the intermediate hole 22 is set to be relatively small, so that the loss of the bonding glue 30 is very limited, and the middle position of the back plate 10 is used to bond the light-emitting chip 40, so as to ensure that there is enough glue to hold the light-emitting chip 40 in the fixing area of ​​the light-emitting chip 40 to fix the light-emitting chip 40.

[0059] The edge holes 21 and the middle holes 22 may be arranged in a variety of ways, for example, the edge holes are located on both sides of the edge of the back plate, and the middle holes are evenly spaced between the edge holes on both sides.

[0060] Step S200: transferring the light emitting chip to the surface of the back plate provided with the adhesive glue.

[0061] like Figure 6 , Figure 8As shown in the figure, in this embodiment, the light-emitting chip 40 is directly transferred onto the surface of the backplane 10 coated with the adhesive liquid 30 through a direct transfer mechanism 50 (such as a laser direct transfer mechanism), so that the light-emitting chip 40 adheres to the surface of the adhesive liquid 30. The adhesive liquid 30 is coated with a certain thickness, so that there is a certain distance between the light-emitting chip 40 and the surface of the backplane 10 at this time. Through this distance, the light-emitting chip 40 will not immediately contact the surface of the backplane 10. When the light-emitting chip 40 slowly moves to the surface of the backplane 10, there is a certain time to squeeze out air bubbles and correct the position of the light-emitting chip 40, so that the light-emitting chip 40 can be more accurately connected to the backplane 10.

[0062] Step S300: Heat the backplane to conduct multiple holes, and the adhesive liquid flows out from the multiple holes to drive the light-emitting chip to move toward the backplane, realizing bonding with the backplane.

[0063] As Figure 6 , Figure 7 , Figure 8 As shown in the figure, in this embodiment, the light-emitting chip 40 is sent into a heating chamber 81 (such as a reflow chamber) for heating. The holes 20 on the backplane 10 are opened through the heating effect, and the adhesive liquid 30 flows out toward the holes 20, thinning the thickness of the adhesive liquid 30 on the backplane 10, thereby driving the light-emitting chip 40 to move downward and gradually approach the surface of the backplane 10. Finally, the light-emitting chip 40 contacts the electrodes of the backplane 10 and realizes eutectic bonding at the heating temperature. In this process, eutectic bonding does not need to be carried out in a high-pressure environment, which optimizes the production process and makes the production equipment used simpler.

[0064] As Figure 1 , Figure 2 As shown in the figure, further, step S300 in this embodiment specifically further includes:

[0065] Step S310: Apply negative pressure adsorption to the light-emitting chip to move the light-emitting chip toward the backplane and contact for eutectic bonding.

[0066] As Figure 8 As shown in the figure, in the specific process, the backplane 10 is sequentially transported in the transport mechanism and passes under the laser direct transfer mechanism 50 in sequence. The light-emitting chip 40 is directly transferred onto the backplane 10 passing by below through the laser direct transfer mechanism 50 in sequence. The backplane 10 receiving the light-emitting chip 40 is transported to the negative pressure adsorption mechanism 70 through the continuous movement of the transport mechanism and is adsorbed by the negative pressure adsorption of the negative pressure adsorption mechanism 70.

[0067] The negative pressure adsorption mechanism 70 can drive the backplane 10 to move up and down. The backplane 10 is pushed upward into the heating chamber 81 by the negative pressure adsorption mechanism 70, and the upward moving negative pressure adsorption mechanism 70 can seal the inlet of the heating chamber 81, so as to stably push the backplane 10 with the light-emitting chip 40 into the heating chamber 81 for negative pressure adsorption and heating.

[0068] The backplane is heated by the heating chamber while the light-emitting chip is adsorbed by the negative pressure adsorption mechanism, so that the electrodes of the light-emitting chip are in contact with the electrodes of the backplane for eutectic bonding. As Figure 6 、 Figure 7 、 Figure 8 shown, in the specific process, the negative pressure adsorption mechanism 70 sends the backplane 10 with the light-emitting chip 40 into the heating chamber 81, and at the same time, negative pressure adsorption and heating are carried out. The heating and negative pressure adsorption make the outflow speed of the diluent faster, and the negative pressure adsorption of the light-emitting chip 40 makes the moving speed of the light-emitting chip 40 towards the backplane 10 faster, thus improving the connection speed between the light-emitting chip 40 and the backplane 10. Moreover, in the process of the adhesive liquid 30 gradually thinning, it is slower than the process of directly squeezing by high pressure, so that the bubbles at the bonding interface can be slowly discharged, avoiding the problem that the bubbles cannot be discharged in time due to the use of high pressure.

[0069] As Figure 2 、 Figure 3 shown, further, in step S300 of this embodiment, the specific steps of making the heat-melted material in a flowing state under heating conditions so that multiple holes are converted from a non-conductive state to a conductive state are as follows:

[0070] The hot melt adhesive on the hole is melted by heating to open the hole. As Figure 4 、 Figure 6 shown, during heating, the hot melt adhesive 23 is directly melted away to open the hole 20, and with the cooperation of the negative pressure suction, the melted hot melt adhesive 23 can quickly break away from the hole 20. Not only does it not require other conditions to open the hole 20, making the process simpler; moreover, the hot melt adhesive 23 can quickly fall off, increasing the opening speed of the hole 20; thus improving the efficiency of the entire transfer process.

[0071] Through the negative pressure generated by the negative pressure adsorption mechanism, the diluent in the adhesive liquid is sucked out from the holes, and at the same time, the light-emitting chip is moved towards the backplane until the receiving adhesive liquid is heated and cured. The vacuum adsorption value generated by the negative pressure adsorption mechanism in this embodiment is: -90 kPa to -60 kPa. The vacuum adsorption value is preferably -81.4 kPa. By using the vacuum adsorption value within this range, the diluent can be attracted to flow out while the light-emitting chip is also attracted towards the backplane. When the amount of the adsorbed diluent reaches a predetermined value (at this predetermined value, the content of the carrier adhesive liquid in the adhesive liquid is high, meeting the bonding and fixing requirements for the light-emitting chip), the light-emitting chip can be stably adsorbed onto the backplane and more accurately docked with the electrodes on the backplane. This ensures the stability of the eutectic bonding and the firmness of the bonding of the light-emitting chip. Through the combined action of heating and negative pressure, the opening of the holes is accelerated. Moreover, through heating, not only the diluent in the adhesive liquid flows out, thereby increasing the concentration of the receiving adhesive liquid, increasing the viscosity of the receiving adhesive liquid, making the outflow speed of the receiving adhesive liquid less than that of the diluent, and retaining the receiving adhesive liquid to the greatest extent; but also with the temperature accumulation during heating, it is beneficial for the receiving adhesive liquid to cure. Before curing, the light-emitting chip moves downward faster through negative pressure, so that the electrodes of the light-emitting chip contact the electrodes on the backplane, and then are fixed, making the fixing process of the light-emitting chip more stable, avoiding the cured light-emitting chip not contacting the backplane, and thus greatly improving the transfer success rate of the light-emitting chip.

[0072] As Figure 3 shown, in another solution, since the light-emitting chip 40 is adsorbed through the holes 20 on the backplane 10, the holes 20 can be correspondingly distributed so that when the light-emitting chip 40 is subjected to negative pressure suction, the electrodes of the light-emitting chip 40 can be more accurately aligned with the electrodes on the backplane 10. Since the aperture of the holes (middle holes 22) in the middle position of the holes 20 is relatively small, a plurality of middle holes 22 are arranged around the electrodes of the light-emitting chip 40, and the arrangement density of the plurality of middle holes 22 gradually increases in the direction close to the electrodes on the backplane 10. Since the density of the middle holes 22 around the electrodes on the backplane 10 is greater, the area where the negative pressure is generated is more concentrated. Therefore, even if the light-emitting chip 40 is slightly offset from the electrodes on the backplane 10 during the downward movement, due to the relatively large negative pressure at the position close to the electrodes on the backplane 10, the suction force on the light-emitting chip 40 in the direction towards the electrodes on the backplane 10 is relatively large, causing the light-emitting chip 40 to be attracted by the negative pressure in the direction towards the electrodes on the backplane 10, so that the electrodes of the slightly offset light-emitting chip 40 can automatically move towards the corresponding electrodes on the backplane 10, thereby making the alignment of the electrodes of the light-emitting chip 40 and the electrodes on the backplane 10 more accurate and the connection more stable after the eutectic bonding of the electrodes.

[0073] As Figure 1 、 Figure 2 shown, step S300 in this embodiment specifically further includes:

[0074] Step S320: Heat the backplane so that the adhesive liquid volatilizes and the light-emitting chip moves towards the backplane.

[0075] In the specific process, not only does the diluent in the adhesive liquid flow out through the holes, but also the diluent in the adhesive liquid volatilizes in the heating environment, thereby accelerating the thinning speed of the adhesive liquid and improving the transfer efficiency.

[0076] As another embodiment:

[0077] As Figure 8 shown, based on the same concept, this embodiment proposes a bonding device. Through this transfer device, the light-emitting chip 40 is transferred and fixed to the backplane 10 by using the chip bonding method of the first embodiment above, realizing a more optimized mass transfer process. Wherein this transfer device mainly includes: a conveying mechanism 60, a direct transfer mechanism 50, a negative pressure adsorption mechanism 70, and a heating mechanism 80. The conveying mechanism 60 is used to carry and convey the backplane 10 coated with the adhesive liquid 30 along a predetermined direction, wherein the backplane 10 has an openable hole 20. The direct transfer mechanism 50 is arranged at the feeding end of the conveying mechanism 60 and is used to place the light-emitting chip 40 on the backplane 10 coated with the adhesive liquid 30. The negative pressure adsorption mechanism 70 is arranged at the output end of the conveying mechanism 60 and is used to generate negative pressure to adsorb the backplane 10. The heating mechanism 80 has a heating chamber 81, and the backplane 10 enters the heating chamber 81 driven by the negative pressure adsorption mechanism 70, and the hole 20 is opened by the heating of the heating chamber 81. Under the combined action of the negative pressure of the negative pressure adsorption mechanism 70 and the heating of the heating chamber 81, part of the adhesive liquid 30 flows out from the hole 20, causing the light-emitting chip 40 to move towards the backplane 10, so that the electrodes of the light-emitting chip 40 and the electrodes on the backplane 10 are in contact for eutectic bonding.

[0078] Compared with the existing high-temperature and high-pressure transfer device, the above transfer device optimizes the structure of the production equipment, enabling the light-emitting chip 40 to be transferred and eutectically bonded under ordinary pressure conditions. Since there is no extrusion of the high pressure on the light-emitting chip 40, it avoids the displacement of the light-emitting chip 40 caused by the extrusion of the high pressure on the light-emitting chip 40, making the connection between the light-emitting chip 40 and the backplane 10 more stable; at the same time, it avoids the light-emitting chip 40 from being damaged, effectively reducing the defect rate of the light-emitting chip 40 during the transfer process. Thus, the qualification rate of mass transfer is greatly improved.

[0079] Further, the negative pressure adsorption mechanism 70 in this embodiment includes: a vacuum adsorption table, which is movably arranged in the vertical direction. The heating chamber 81 is located above the vacuum adsorption table. The heating chamber 81 is a reflux chamber, and an inlet is opened below the reflux chamber. The vacuum adsorption table is docked with the inlet by moving upward, so that the adsorbed backplane 10 is located in the reflux chamber. By using the cooperation of the vacuum adsorption table and the reflux chamber, the inlet of the reflux chamber is closed, so that the temperature in the reflux chamber is stable, and the negative pressure in the reflux chamber is less affected by the air at the inlet, ensuring the stability of negative pressure adsorption. During the reflux heating process of the light-emitting chip 40, under the action of the suction force, the electrodes of the light-emitting chip 40 are strongly contacted with the electrodes of the backplane 10, and eutectic bonding is achieved in a stable high-temperature environment. In a stable negative pressure and heating environment, the bonding material is more evenly distributed, improving the connection success rate of the light-emitting chip 40.

[0080] Another implementation manner is:

[0081] Based on the same concept, this embodiment proposes a display panel, as Figure 6 or Figure 7 shown, which includes: a backplane 10 and a light-emitting chip 40. The light-emitting chip 40 is connected to the backplane 10 by the above chip bonding method. Holes 20 are opened on the backplane 10, and the light-emitting chip 40 is fixed on the backplane 10 by an adhesive liquid 30;

[0082] During the eutectic bonding process between the light-emitting chip and the backplane, by heating the backplane, a plurality of the holes are changed from a non-conductive state to a conductive state, so that the adhesive liquid flows out of the plurality of holes and drives the light-emitting chip to move towards the backplane.

[0083] Further, the holes 20 in this embodiment are composed of edge holes 21 and middle holes 22. The functions and distribution relationships of the holes 20 refer to the description in the first embodiment, and will not be repeated here. The production process of the display panel is made simpler and the production cost is lower.

[0084] The light-emitting chip 40 in the above embodiments may be an LED chip, a Mini-LED chip or a Micro-LED chip.

[0085] As another implementation manner:

[0086] Based on the same concept, this embodiment proposes a display device, which includes the above display panel and optimizes the production process of the display device. The display device may be, but is not limited to, electronic terminal products such as mobile phones, computers (including laptop computers and desktop computers), televisions, AR glasses, vehicle-mounted terminals, and outdoor display large screens.

[0087] In summary, the embodiments of the present application propose a chip bonding method, a bonding device, a display panel, and a display device. By opening an openable hole in the backplane, applying an adhesive liquid on the backplane and placing a light-emitting chip, and moving the backplane into a heating chamber, the hole is opened during heating, so that part of the adhesive liquid flows out and volatilizes and consumes to become thinner, and the light-emitting chip moves downward and realizes eutectic bonding with the electrode of the backplane without pressing under the action of suction. The transfer process is optimized, the equipment requirements are reduced, and the production cost is reduced. And it effectively reduces the defect rate of the light-emitting chip during the transfer process, makes the distribution of the bonding material more uniform, avoids bubbles at the bonding interface, and reduces the probability of the light-emitting chip shifting; thereby greatly improving the success rate of chip transfer.

[0088] It should be understood that the application of the present application is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present application.

Claims

1. A chip bonding method, characterized in that, Comprising the steps of: Providing a backplane, on which a plurality of unconducted holes are provided, and the entire layer of the backplane is coated with an adhesive liquid; Transferring a light-emitting chip to the surface of the backplane provided with the adhesive liquid; Heating the backplane to conduct a plurality of the holes, and the adhesive liquid flows out of the plurality of holes to drive the light-emitting chip to move towards the backplane, thereby realizing bonding with the backplane.

2. The chip bonding method according to claim 1, wherein The step of providing a backplane, on which a plurality of unconducted holes are provided, includes: Providing a backplane, and a plurality of unconducted holes are provided at the middle position and the two side edge positions relative to the middle position of the backplane, wherein the size of the holes at the middle position is smaller than the size of the holes at the two side edge positions.

3. The chip bonding method according to claim 1 or 2, characterized in that The spaces between the plurality of unconducted holes are filled with a heat-melted material, and the heat-melted material is in a flowing state under heating conditions, so that the plurality of holes are changed from an unconducted state to a conducted state.

4. The chip bonding method according to claim 3, wherein The heat-melted material includes hot melt adhesive.

5. The chip bonding method according to claim 1 or 2, characterized in that, In the step of heating the backplane to conduct a plurality of the holes, and the adhesive liquid flows out of the plurality of holes to drive the light-emitting chip to move towards the backplane, it further includes: Heating the backplane to volatilize the adhesive liquid so that the light-emitting chip moves towards the backplane.

6. The chip bonding method according to claim 1 or 2, characterized in that, In the step of heating the backplane to conduct a plurality of the holes, and the adhesive liquid flows out of the plurality of holes to drive the light-emitting chip to move towards the backplane, it further includes: Performing negative pressure adsorption on the light-emitting chip to make the light-emitting chip move towards the backplane and contact to perform eutectic bonding.

7. A display panel, characterized in that Comprising: A backplane and a light-emitting chip; A plurality of holes are provided on the backplane, and the light-emitting chip is fixed on the backplane through an adhesive liquid; wherein, During the bonding process between the light-emitting chip and the backplane, by heating the backplane, a plurality of the holes are changed from an unconducted state to a conducted state, so that the adhesive liquid flows out of the plurality of holes to drive the light-emitting chip to move towards the backplane.

8. The display panel according to claim 7, wherein, A plurality of the holes are provided at the middle position and the edge positions on both sides relative to the middle position of the backplane; wherein, the size of the holes at the middle position is smaller than the size of the holes at the two side edge positions.

9. The display panel according to claim 8, wherein The arrangement density of the holes at the middle position gradually increases along the direction close to the electrode of the backplane.

10. A display device, characterized in that, Comprising a display panel according to any one of claims 7-9.

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