Mass transfer method, transfer plate and driving plate

Abstract

The invention relates to a mass transfer method, a transfer plate and a driving plate. A transfer plate in the mass transfer method comprises a plurality of light-emitting chips, chip electrodes of the light-emitting chips are arranged far away from the transfer plate, at least one protruding part is arranged on the surface of the side, far away from the transfer plate, of each chip electrode, a plurality of bonding electrodes and a flexible buffer layer are arranged on a driving plate, and the flexible buffer layer covers the bonding electrodes. According to the technical scheme, the protruding parts are arranged on the chip electrodes of the light-emitting chip, and the flexible buffer layer capable of covering the bonding electrodes is arranged on the driving plate, so that when the light-emitting chip falls onto the flexible buffer layer, the protruding parts on the chip electrodes can be completely or partially inserted into the flexible buffer layer to be buffered and fixed; therefore, the yield of mass transfer is prevented from being affected by displacement of the light-emitting chip.

Description

Technical Field

[0001] The present invention relates to the technical field of display devices, and in particular to a mass transfer method, a transfer plate and a drive plate. Background Art

[0002] Light-emitting diodes are semiconductor diodes that can convert electrical energy into light energy and are widely used in display devices and backlight sources. The chip is the core component of the light-emitting diode, and the micro light-emitting diode chip is a diode chip with a size of micrometers.

[0003] In the existing micro-LED display manufacturing process, mass transfer is the key point of technological breakthrough. Among the many mass transfer technologies, the suspended direct transfer technology has the advantages of simple process, low cost and strong feasibility. In the current mass transfer process of micro-LEDs, when the chip is peeled off from the transfer board and falls onto the driver board, the chip will be impacted during the peeling process, and the stress inside the chip itself will cause the chip to move due to bouncing and other problems after it falls onto the driver board, resulting in poor offset, which seriously affects the direct transfer yield. Therefore, how to improve the yield of mass transfer is an urgent problem to be solved. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned related technologies, the purpose of the present application is to provide a mass transfer method, a transfer plate and a driving board, aiming to solve the problem that in the current mass transfer process, the light-emitting chip falls onto the driving board and is prone to bounce and shift, resulting in reduced yield.

[0005] A mass transfer method, comprising:

[0006] A transfer plate is provided, a plurality of light-emitting chips are fixed on one side of the transfer plate, the chip electrodes of the light-emitting chips are arranged away from the transfer plate, and a convex portion is provided on the surface of the chip electrodes away from the transfer plate;

[0007] A driving board is provided, on which a plurality of bonding electrodes and a flexible buffer layer are arranged, wherein the flexible buffer layer covers each of the bonding electrodes;

[0008] The chip electrodes of the transfer plate are aligned with the bonding electrodes of the driving plate, and each light-emitting chip is peeled off from the transfer plate so that the raised portions of the chip electrodes are fully or partially inserted into the flexible buffer layer.

[0009] In the above-mentioned mass transfer method, the transfer plate includes: a plurality of light-emitting chips, and the chip electrodes of the light-emitting chips are arranged away from the transfer plate, and the surface of the chip electrode away from the transfer plate is provided with at least one protrusion, and a plurality of bonding electrodes and a flexible buffer layer covering each electrode are provided on the driving plate, and a plurality of bonding electrodes and a flexible buffer layer are provided on the driving plate, and the flexible buffer layer covers each bonding electrode. In this way, when the light-emitting chip falls onto the flexible buffer layer, the protrusion on the chip electrode can be fully or partially inserted into the flexible buffer layer for buffering and fixing, thereby avoiding displacement of the light-emitting chip and affecting the yield of mass transfer.

[0010] Optionally, the shape of the protrusion is such that its cross-sectional area gradually decreases in a direction away from the chip electrode.

[0011] In the above-mentioned light-emitting chip, the cross-sectional area of ​​the protrusion is gradually reduced in the direction away from the chip electrode, which is conducive to the protrusion being inserted into the flexible buffer layer.

[0012] Optionally, along an extension direction perpendicular to the driving board, a height H1 of a portion of the flexible buffer layer higher than the bonding electrode is at least greater than half of a height H2 of the protruding portion.

[0013] For the above-mentioned light-emitting chip, the thickness of the flexible buffer layer is set so that the height H1 of the portion higher than the bonding electrode is at least greater than half of the height H2 of the protruding portion, so as to prevent the light-emitting chip from popping out and falling off the buffer layer after falling onto the buffer layer.

[0014] Optionally, a height H1 of a portion of the flexible buffer layer higher than the bonding electrode is greater than a height H2 of the protruding portion, and after the protruding portion is inserted into the flexible buffer layer, the following further comprises:

[0015] Applying pressure to the transfer plate from a side away from the light-emitting chip so that the protrusion contacts the bonding electrode;

[0016] The chip electrode is bonded to the bonding electrode.

[0017] For the above-mentioned light-emitting chip, after the protrusion of the light-emitting chip is inserted into the flexible buffer layer, effective contact between the protrusion and the bonding electrode cannot be guaranteed, so the light-emitting chip needs to be pressed down until it contacts the bonding electrode before bonding.

[0018] Optionally, a plurality of barbs or burrs are provided on the surface of the raised portion.

[0019] Based on the same inventive concept, the present application also provides a transfer plate, comprising:

[0020] A transfer substrate, which is used to fix a plurality of light-emitting chips in a mass transfer process;

[0021] A plurality of the light-emitting chips are fixed on the transfer substrate, the chip electrodes of the light-emitting chips are located on a side away from the transfer substrate, and at least one protrusion is provided on the surface of the chip electrodes on a side away from the transfer substrate.

[0022] The above-mentioned transfer plate arranges the chip electrode of the light-emitting chip on the side away from the transfer substrate, and at least one protrusion is provided on the surface of the chip electrode on the side away from the transfer plate. In this way, during the mass transfer process, when the light-emitting chip is peeled off and falls onto the driving board, the protrusion on the chip electrode can be inserted into the flexible buffer layer on the driving board to play a buffering and fixing role, thereby avoiding the displacement of the light-emitting chip and affecting the yield of the mass transfer.

[0023] Based on the same inventive concept, the present application also provides a driving board, comprising:

[0024] Driver substrate;

[0025] A plurality of bonding electrodes, wherein the bonding electrodes are arranged on a surface of one side of the driving substrate;

[0026] The flexible buffer layer is arranged on the same side of the bonding electrodes on the driving substrate, and the flexible buffer layer covers each of the bonding electrodes.

[0027] The above-mentioned driving board is provided with a flexible buffer layer on the same side of the driving substrate as the bonding electrode, and the flexible buffer layer covers each of the bonding electrodes. Therefore, when the transfer plate provided by the present invention peels off the light-emitting chip and drops it onto the driving board, the protrusion on the chip electrode can be inserted into the flexible buffer layer on the driving board to play a buffering and fixing role, thereby avoiding displacement of the light-emitting chip and affecting the yield of mass transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a flow chart of a mass transfer method provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the structure of a transfer plate provided by an embodiment of the present invention;

[0030] Figure 3 Structural schematic diagrams of three other transfer plates provided in embodiments of the present invention;

[0031] Figure 4 A schematic diagram of a partially enlarged structure of another transfer plate provided in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of the structure of a driving board provided by an embodiment of the present invention;

[0033] Figure 6A schematic diagram of a structure including a transfer plate and a drive plate provided in an embodiment of the present invention;

[0034] Figure 7 A flow chart of another mass transfer method provided for another optional embodiment of the present invention

[0035] Figure 8 A schematic structural diagram of four light-emitting chips on one side of a chip electrode provided by another optional embodiment of the present invention;

[0036] Fig. 9 Another optional embodiment of the present invention provides Figure 5 A partial enlarged view of the structure shown;

[0037] Fig.10 A schematic flow chart of a mass transfer method provided for another optional embodiment of the present invention;

[0038] Fig.11 A schematic flow chart of a mass transfer method provided for another optional embodiment of the present invention;

[0039] Fig.12 A process diagram corresponding to the complete process steps of a mass transfer method provided in an embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 100-epitaxial layer; 200-chip electrode; 300-protrusion; 10-driving substrate; 20-bonding electrode; 30-flexible buffer layer; 50-transfer substrate; 60-light-emitting chip. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present 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 present application more thoroughly and comprehensively understood.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0044] Among the existing mass transfer technologies, the suspended direct transfer technology has the advantages of simple process, low cost and strong feasibility. During the mass transfer process of the existing micro light-emitting diodes, when the chip is peeled off from the transfer board and falls onto the driving board, the impact force on the chip during the peeling process and the stress inside the chip itself will cause the chip to move after falling onto the driving board, resulting in an offset defect, which seriously affects the direct transfer yield.

[0045] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0046] This embodiment provides a mass transfer method, comprising: providing a transfer plate, a plurality of light-emitting chips 60 are fixed on one side of the transfer plate, the chip electrodes 200 of the light-emitting chips 60 are arranged away from the transfer plate, and at least one protrusion 300 is provided on the surface of the chip electrode 200 away from the transfer plate;

[0047] A driving board is provided, on which a plurality of bonding electrodes 20 and a flexible buffer layer 30 are provided, and the flexible buffer layer 30 covers each of the bonding electrodes 20;

[0048] The chip electrode 200 of the transfer plate is aligned with the bonding electrode 20 of the driving plate, and each of the light-emitting chips 60 is peeled off from the transfer plate, so that the protrusion 300 of the chip electrode 200 is fully or partially inserted into the flexible buffer layer 30 .

[0049] See also Figure 1 , Figure 1 A flow chart of a mass transfer method provided in this embodiment. The mass transfer method includes:

[0050] S101, providing a transfer plate, with a plurality of light-emitting chips 60 fixed on one side of the transfer plate, the chip electrodes 200 of the light-emitting chips 60 being arranged away from the transfer plate, and at least one protrusion 300 being arranged on the surface of the chip electrode 200 away from the transfer plate.

[0051] The transfer plate provided in this embodiment has a light emitting chip 60 fixed thereon and at least one protrusion 300 disposed on the chip electrode 200. The optional range of the protrusion height d of the protrusion 300 includes but is not limited to being controlled within the range of 1um<d<2um.

[0052] S102 , providing a driving board, on which a plurality of bonding electrodes 20 and a flexible buffer layer 30 are disposed, and the flexible buffer layer 30 covers each bonding electrode 20 .

[0053] The driving board provided in this embodiment is covered with a flexible buffer layer 30 and a plurality of bonding electrodes 20 on one side, and the flexible buffer layer 30 covers each bonding electrode 20, so that when the light-emitting chip 60 falls onto the flexible buffer layer 30, the protrusion 300 on the chip electrode 200 of the light-emitting chip 60 can be inserted into the flexible buffer layer 30 to play a fixing and buffering role.

[0054] S103 , aligning the chip electrode 200 of the transfer plate with the bonding electrode 20 of the driving plate, and peeling each light-emitting chip 60 from the transfer plate, so that the protrusion 300 of the chip electrode 200 is fully or partially inserted into the flexible buffer layer 30 .

[0055] In this embodiment, the method for peeling the light-emitting chip 60 from the transfer plate includes but is not limited to peeling by laser. When the light-emitting chip 60 is peeled from the transfer plate by laser, nitrogen is generated on the peeling surface. After peeling, the light-emitting chip 60 falls onto the flexible buffer layer 30 under the impact force of nitrogen and gravity.

[0056] This embodiment provides a mass transfer method, wherein the structure of the transfer plate used can be seen in Figure 2 , Figure 2 A schematic diagram of the structure of a transfer plate provided in an embodiment. The transfer plate includes a transfer substrate 50 and a light-emitting chip 60, and the light-emitting chip 60 includes: an epitaxial layer 100, the outermost side of the epitaxial layer 100 in the growth direction A is a first side; a chip electrode 200, which is arranged on the first side of the epitaxial layer 100, and the side of the chip electrode 200 away from the epitaxial layer 100 is a second side; and at least one protrusion 300 is formed in a direction away from the chip electrode 200.

[0057] In this embodiment, the transfer substrate 50 is used to fix a number of light-emitting chips 60 in the mass transfer process; the transfer substrate 50 can also be used as a substrate for growing the light-emitting chip 60, that is, a growth substrate, and the growth substrate can be a transparent material, and the optional transparent material includes inorganic materials or III-V semiconductor materials. Inorganic materials include silicon carbide (SiC), germanium (Ge), sapphire (Sapphire), lithium aluminate (LiAlO2), zinc oxide (ZnO), glass or quartz. III-V semiconductor materials include indium phosphide (InP), gallium phosphide (GaP), gallium nitride (GaN), and aluminum nitride (AlN) materials. The growth substrate should have sufficient strength to mechanically support the epitaxial layer and be able to transmit light emitted from the epitaxial layer 100. The thickness of the growth substrate can be selected to be 50μm or more. In addition, in order to facilitate the subsequent possible bonding process that requires mechanical processing (thinning) of the substrate, the thickness of the selected growth substrate is generally not more than 300μm. In this embodiment, the epitaxial layer 100 includes a conventional mini LED epitaxial layer 100 structure and a micro LED epitaxial layer 100 structure. The chip electrode 200 is arranged at the outermost side of the epitaxial layer 100 in the growth direction A. Such a structure facilitates the subsequent transfer and bonding of the light-emitting chip 60.

[0058] See also Figure 2 and Figure 3 , Figure 3 Schematic diagram of the structures of three other transfer plates provided for this embodiment. In this embodiment, the raised portion 300 serves to limit the position of the light-emitting chip 60. When the light-emitting chip 60 falls onto the driving board, the raised portion 300 can be inserted into the flexible buffer layer 30 of the driving board to fix the light-emitting chip 60. In this embodiment, one light-emitting chip 60 needs to be provided with at least one raised portion 300. The raised portion 300 can be provided on one of the chip electrodes 200, or on both chip electrodes 200. When provided on both chip electrodes 200, the light-emitting chip 60 can be prevented from falling onto the flexible buffer layer 30 and causing rotational displacement. At the same time, the provision of two raised portions 300 can also serve to keep the light-emitting chip 60 horizontal, and prevent the light-emitting chip 60 from being skewed when bonded to the driving board. It can be understood that the number of raised portions 300 is not limited to Figure 2 and Figure 3 The two shown in the figure can also be provided with one, and when it is provided with two or more protrusions 300, it can also prevent the light-emitting chip 60 from rotating and moving. At the same time, a chip electrode 200 can also be provided with multiple protrusions 300; the setting position of the protrusion 300 is not limited to Figure 2 and Figure 3As shown, in actual application, it can be set at any position above the chip electrode 200 as needed, for example, it can be set at the edge of the chip electrode 200. When two protrusions 300 are set on one chip electrode 200, they can be symmetrically set on the chip electrode 200. The specific structure and shape of the protrusion 300 are not limited to Figure 2 The needle-like structure shown in FIG. 1 is wide at the bottom and narrow at the top. In some cases, the protrusion 300 may be set as a rectangular structure, or a plurality of barbs or thorns may be set on the surface of the protrusion 300. Figure 4 , Figure 4 This is a partial enlarged view of a transfer plate provided in this embodiment. Figure 4 A plurality of burrs are arranged on the surface of the raised portion 300. The presence of the barbs or burrs can prevent the light emitting chip 60 from being ejected again after falling onto the driving board.

[0059] This embodiment provides a method for mass transfer, wherein the structure of the driving board used can be seen in Figure 5 , Figure 5 A schematic diagram of the structure of a driving board provided in this embodiment. Figure 5 The middle driving board includes a driving substrate 10, a bonding electrode 20 and a flexible buffer layer 30, wherein the driving substrate 10 has a corresponding driving circuit, and the driving circuit is connected to each bonding electrode 20 to realize the corresponding function. The driving circuit can be an active matrix circuit (Active Matrix, AM) or a passive matrix circuit (Passive Matrix, PM) according to different driving modes. The position of the bonding electrode 20 corresponds to the chip electrode 200 of the light-emitting chip 60, and the chip electrode 200 is fixed and electrically connected to the bonding electrode 20 through bonding. The flexible buffer layer 30 covers the driving substrate 10 and the bonding electrode 20, and serves the purpose of buffering and fixing the light-emitting chip 60 that falls off the transfer plate.

[0060] In this embodiment, the driving substrate 10 may be selected from, but not limited to, a glass substrate, a resin substrate, a PCB substrate, and a flexible PCB substrate.

[0061] In this embodiment, the bonding electrode 20 is used to bond with the chip electrode 200 . The bonding electrode 20 may exist as a part of the driving circuit, or may be manufactured separately to facilitate bonding with the light-emitting chip 60 .

[0062] In this embodiment, the materials that can be used for the flexible buffer layer 30 include, but are not limited to, flexible pyrolytic adhesives, flexible photolytic adhesives, organic synthetic resins and other adhesives with deformable properties.

[0063] This embodiment provides a mass transfer method, in which the structure of the light emitting chip 60 when it is peeled off from the transfer plate and falls onto the driving plate can be seen in FIG. Figure 6 , Figure 6 A schematic diagram of a structure including a transfer plate and a driving plate is provided for this embodiment. The chip electrode 200 of the transfer plate is aligned with the bonding electrode 20 of the driving plate, that is, the chip electrode 200 of the light-emitting chip 60 is aligned with the corresponding bonding electrode 20; after the chip electrode 200 of the light-emitting chip 60 is aligned with the corresponding bonding electrode 20, the light-emitting chip 60 can be peeled off from the transfer substrate 50 by laser, and when the light-emitting chip 60 falls onto the flexible buffer layer 30, due to a certain falling speed, the protrusion 300 on the chip electrode 200 will be fully or partially inserted into the flexible buffer layer 30.

[0064] Another optional embodiment of the present invention:

[0065] This embodiment further expands and explains the mass transfer method based on the above embodiment, and the content is as follows:

[0066] In another optional embodiment, the cross-sectional area of ​​the protrusion 300 gradually decreases in a direction away from the chip electrode 200 .

[0067] See also Figure 2 and Figure 3 Setting the shape of the protrusion 300 to a shape in which the cross-sectional area gradually decreases in a direction away from the chip electrode 200 facilitates the protrusion to be inserted into the flexible buffer layer 30 .

[0068] In another optional embodiment, two protrusions 300 are disposed on the surface of the chip electrode 200 , and the two protrusions 300 are symmetrically arranged on the surface of the chip electrode 200 .

[0069] See also Figure 3 There are two raised portions 300 on the surface of the chip electrode 200, and the two raised portions 300 are symmetrically arranged on the surface of the chip electrode 200, so that the light-emitting chip 60 can be subjected to more uniform force when it falls onto the flexible buffer layer 30, thereby improving the reliability of the light-emitting chip 60. At the same time, since the raised portions 300 are symmetrically arranged, the light-emitting chip 60 can also fall onto the flexible buffer layer 30, and the light-emitting chip 60 can remain horizontal after bonding is completed.

[0070] In another optional embodiment, before providing a transfer plate, the method further includes:

[0071] A conductive layer is formed on the surface of the chip electrode 200 away from the transfer plate;

[0072] The central portion of the conductive layer is removed to form the protrusion 300 at the edge of the conductive layer.

[0073] like Figure 7 As shown, Figure 7A schematic flow chart of another mass transfer method provided in this embodiment.

[0074] In step S101, a transfer plate is provided. The following steps are also included:

[0075] S601, making a conductive layer on the surface of the chip electrode 200 away from the transfer plate.

[0076] In this embodiment, the method of covering the conductive layer on the surface of the chip electrode 200 away from the transfer plate includes but is not limited to depositing a conductive layer on the chip electrode 200 by evaporation, covering a conductive layer on the chip electrode 200 by printing, and forming a conductive layer on the chip electrode 200 by ion implantation. The purpose of covering the chip electrode 200 with a conductive layer is to reduce the impact of the protrusion 300 made of the conductive layer on the electrical performance of the light-emitting chip 60, so it is necessary to set it with conductive performance.

[0077] S602 , removing the central portion of the conductive layer to form a protrusion 300 at the edge of the conductive layer.

[0078] Removing the center of the conductive layer and leaving only the edge of the conductive layer can naturally form Figure 3 As shown in the figure, it can be understood that the central part of the conductive layer can be removed by removing only a part of the central part or by removing the entire central part. The structure of the protrusion 300 after removing the central part can be seen in FIG. Figure 8 , Figure 8 The schematic diagrams of the structures of the four light-emitting chips 60 provided in this embodiment on one side of the chip electrode 200 are shown. Figure 7-1 The raised portion 300 in the embodiment is a long strip-shaped raised portion. Figure 7-2 The raised portion 300 in the figure is a round dot-shaped raised portion. Figure 7-3 The raised portion 300 is divided into horizontal and vertical long strip-shaped raised portions. Figure 7-4 The protrusions 300 in the embodiment are presented as square dot protrusions. It is understood that the number, shape and position of the protrusions 300 are not limited to Figure 8 As shown, the deformed structure outputted on the basis of meeting the idea of ​​the present invention belongs to the protection scope of the present invention. It should be noted that the common application field of mass transfer is in the transfer process of micro light-emitting diodes, and the chip size of micro light-emitting diodes is usually around 8μm. Therefore, when the light-emitting chip 60 of this embodiment is a micro light-emitting chip, the height of the protrusion 300 in the thickness direction away from the second side of the chip electrode 200 is greater than 1um and less than 2um, and the spacing between two adjacent protrusions 300 is greater than 0um and less than 2um. .

[0079] In another optional embodiment, step S602, removing the central portion of the conductive layer to form a protrusion 300 at the edge of the conductive layer, includes:

[0080] Etching away the central portion of the conductive layer using a chemical etching process to form a protrusion 300 at the edge of the conductive layer;

[0081] Alternatively, a physical etching process is used to etch away the central portion of the conductive layer to form the protrusion 300 at the edge of the conductive layer.

[0082] The chemical etching process can adopt the conventional mask etching method, that is, a mask layer is first covered on the conductive layer, so that after being soaked in chemical reagents, the part covered by the mask layer is retained, and the part not covered by the mask layer is etched away. The physical etching process can be etched by a conventional etching machine.

[0083] In another optional embodiment, when a physical etching process is used to etch away a central portion of the conductive layer to form a protrusion 300 at an edge of the conductive layer, the cross-sectional area of ​​the protrusion 300 gradually decreases in a direction away from the chip electrode 200 .

[0084] In this embodiment, the side surface of the protrusion 300 of the limiting component is perpendicular to the second side of the chip electrode 200 ; or, the side surface of the protrusion 300 of the limiting component gradually converges in a direction away from the second side of the chip electrode 200 .

[0085] See also Figure 2 and Figure 3 . Figure 3 The side of the middle protrusion 300 is perpendicular to the second side of the chip electrode 200 and is a vertical thin strip. Since the protrusion 300 needs to be inserted into the flexible buffer layer 30 of the driving board, the width of the protrusion 300 of this structure should not be too wide and is usually about 0.5μm. Figure 4 The side surface of the middle protrusion 300 presents a right triangle structure, and a tip is formed at the top. Due to the existence of the tip, the width of the contact portion between the protrusion structure and the chip electrode 200 is smaller than that of the chip electrode 200. Figure 3 The raised portion 300 can be made wider to fit a larger light emitting chip 60. It is understandable that Figure 3 The structure of the protrusion 300 in the figure includes, but is not limited to, an isosceles triangle and a trapezoid in addition to a right triangle.

[0086] In another optional embodiment, along the extension direction perpendicular to the driving board, the height H1 of the portion of the flexible buffer layer 30 higher than the bonding electrode 20 is at least greater than half of the height H2 of the protrusion 300 .

[0087] See also Fig. 9 , Fig. 9 For this embodiment Figure 6 A partial enlarged view, where the height of the portion of the flexible buffer layer 30 that is higher than the bonding electrode 20 is H1, and the height of the protrusion 300 is H2, where H1>1 / 2H2. It is required that H1 is at least greater than half of H2 to ensure that the protrusion 300 has sufficient insertion depth to better buffer and fix the light-emitting chip 60.

[0088] In another optional embodiment, the height H1 of the portion of the flexible buffer layer 30 higher than the bonding electrode 20 is greater than the height H2 of the protrusion 300, and after the protrusion 300 is inserted into the flexible buffer layer 30, the following further comprises:

[0089] Applying pressure to the transfer plate from a side away from the light emitting chip 60 so that the protrusion 300 contacts the bonding electrode 20;

[0090] The chip electrode 200 is bonded to the bonding electrode 20 .

[0091] See also Fig.10 , Fig.10 A schematic flow chart of another mass transfer method provided in this embodiment. The height H1 of the portion of the flexible buffer layer 30 that is higher than the bonding electrode 20 is greater than the height H2 of the protrusion 300, and after the protrusion 300 is inserted into the flexible buffer layer 30, the following steps are further included:

[0092] S901 , applying pressure to the transfer plate from a side away from the light emitting chip 60 , so that the protrusion 300 contacts the bonding electrode 20 .

[0093] Since the thickness of the flexible buffer layer 30 above the bonding electrode 20 is greater than the protruding height of the protruding portion 300, the protruding portion 300 cannot ensure effective contact with the bonding electrode 20 on the driving board after the light-emitting chip 60 falls onto the flexible buffer layer 30. The light-emitting chip 60 needs to be pressed downward in the direction of the driving board so that the protruding portion 300 contacts the bonding electrode 20 on the driving board before bonding can be performed.

[0094] S902 , bonding the chip electrode 200 to the bonding electrode 20 .

[0095] In step S902 , the chip electrode 200 is bonded to the bonding electrode 20 , wherein bonding methods include but are not limited to thermal compression bonding, laser bonding and gold-gold bonding.

[0096] In another optional embodiment, after bonding the chip electrode 200 to the bonding electrode 20, the method further includes:

[0097] The flexible buffer layer 30 is removed.

[0098] See also Fig.11 , Fig.11 A schematic flow chart of another mass transfer method provided in this embodiment. Step S702: Bond the chip electrode 200 to the bonding electrode 20. Then, the following steps are included:

[0099] S903 , removing the flexible buffer layer 30 .

[0100] After the bonding of the light emitting chip 60 is completed in this embodiment, the flexible buffer layer 30 needs to be removed to avoid the problem of desoldering caused by the flexible buffer layer 30 squeezing the light emitting chip 60. The method of removing the flexible buffer layer 30 needs to be selected according to the material of the flexible buffer layer 30. For example, when the flexible buffer layer 30 is made of flexible pyrolysis glue, the flexible buffer layer 30 can be removed by heating, when the flexible buffer layer 30 is made of flexible photolysis glue, the flexible buffer layer 30 can be removed by light, and when the flexible buffer layer 30 is made of organic synthetic resin, the flexible buffer layer 30 can be removed by organic solvent.

[0101] In another optional embodiment, the material of the protrusion 300 includes any one of tin, copper and gold.

[0102] In this embodiment, the raised portion 300 is made of a conductive layer and has conductive properties. Therefore, its optional preparation materials include but are not limited to any one of tin, copper and gold, among which tin is a common material in chip welding bonding. When the chip is bonded, the raised portion 300 made of tin can be directly used as one of the welding bonding materials by heating, thereby playing a role in welding bonding.

[0103] The process diagram corresponding to the complete process steps of a mass transfer method provided by the present invention can be found in Fig.12 , wherein steps S901 and S902 can be completed in one process step, for example, the light emitting chip 60 is pressed down and heated at the same time to complete the bonding process of the light emitting chip 60 .

[0104] Another optional embodiment of the present invention:

[0105] This embodiment provides a transfer plate, which includes: a transfer substrate 50, which is used to fix a number of light-emitting chips 60 in a mass transfer process;

[0106] A plurality of light emitting chips 60 are fixed on the transfer substrate 50 , and the chip electrode 200 of the light emitting chip 60 is located at a side away from the transfer substrate 50 , and at least one protrusion 300 is provided on the surface of the chip electrode 200 away from the transfer substrate.

[0107] See also Figure 2The transfer plate includes: a transfer substrate 50, which is used to fix a plurality of light-emitting chips 60 during the mass transfer process; a plurality of light-emitting chips 60, wherein the light-emitting chips 60 are fixed on the transfer substrate 50, and the chip electrode 200 of the light-emitting chip 60 is located on a side away from the transfer substrate 50, and at least one protrusion 300 is provided on the surface of the chip electrode 200 on a side away from the transfer substrate 50.

[0108] This embodiment also provides a driving board, including:

[0109] A driving substrate 10;

[0110] A plurality of bonding electrodes 20, wherein the bonding electrodes 20 are disposed on a surface of one side of the driving substrate 10;

[0111] The flexible buffer layer 30 is disposed on the same side of the key electrodes on the driving substrate 10 , and the flexible buffer layer 30 covers each of the key electrodes 20 .

[0112] See also Figure 5 , the driving board includes: a driving substrate 10, and the driving substrate 10 also includes a driving circuit ( Figure 5 The driving substrate 10 includes a bonding electrode 20, which is located on a surface of one side of the driving substrate 10 and is electrically connected to the driving circuit; a flexible buffer layer 30, which is arranged on a side of the driving substrate 10 corresponding to the bonding electrode 20, and the flexible buffer layer 30 covers each of the bonding electrodes 20.

[0113] The present embodiment provides a transfer plate and a driving plate, on which the chip electrode 200 of the light-emitting chip 60 is arranged on a side away from the transfer substrate 50, and at least one protrusion 300 is provided on the surface of the chip electrode 200 on the side away from the transfer plate, and a flexible buffer layer 30 is provided on the same side of the driving plate as the bonding electrode 20, and the flexible buffer layer 30 covers each of the bonding electrodes 20, so that during the process of mass transfer, when the light-emitting chip 60 is peeled off and falls onto the driving board, the protrusion 300 on the chip electrode 200 can be inserted into the flexible buffer layer 30 on the driving board to play a role of buffering and fixing, thereby avoiding displacement of the light-emitting chip 60 and affecting the yield of mass transfer.

[0114] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A mass transfer method, characterized in that: include: A transfer plate is provided, a plurality of light-emitting chips are fixed on one side of the transfer plate, chip electrodes of the light-emitting chips are arranged away from the transfer plate, and at least one protrusion is provided on the surface of the chip electrodes away from the transfer plate; Providing a driving board, on which a plurality of bonding electrodes and a flexible buffer layer are disposed, wherein the flexible buffer layer covers each of the bonding electrodes; The chip electrodes of the transfer plate are aligned with the bonding electrodes of the driving plate, and each of the light-emitting chips is peeled off from the transfer plate so that the raised portions of the chip electrodes are fully or partially inserted into the flexible buffer layer.

2. The method for mass transfer according to claim 1, wherein: The shape of the protrusion is such that the cross-sectional area thereof gradually decreases in a direction away from the chip electrode.

3. The method for mass transfer according to claim 2, wherein: The chip electrode surface is provided with two protrusions, and the two protrusions are symmetrically arranged on the chip electrode surface.

4. The method for mass transfer according to claim 1, wherein: Before providing a transfer plate, the method further includes: Making a conductive layer on the surface of the chip electrode away from the transfer plate; A central portion of the conductive layer is removed to form the protrusion at an edge of the conductive layer.

5. The mass transfer method according to claim 1, wherein: Along the extending direction perpendicular to the driving board, a height H1 of a portion of the flexible buffer layer higher than the bonding electrode is at least greater than half of a height H2 of the protruding portion.

6. The method for mass transfer according to claim 5, wherein: The height H1 of the portion of the flexible buffer layer higher than the bonding electrode is greater than the height H2 of the protrusion, and after the protrusion is inserted into the flexible buffer layer, the following further comprises: Applying pressure to the transfer plate from a side away from the light-emitting chip so that the protrusion contacts the bonding electrode; The chip electrode is bonded to the bonding electrode.

7. The method for mass transfer according to claim 1, wherein: The surface of the raised portion is provided with a plurality of barbs or thorns.

8. The method for mass transfer according to any one of claims 1 to 7, characterized in that: The material of the protrusion includes any one of tin, copper and gold.

9. A transfer plate, characterized in that: include: A transfer substrate, which is used to fix a plurality of light-emitting chips in a mass transfer process; A plurality of the light-emitting chips are fixed on the transfer substrate, the chip electrodes of the light-emitting chips are located on a side away from the transfer substrate, and at least one protrusion is provided on the surface of the chip electrodes on a side away from the transfer substrate.

10. A driving plate, characterized in that: include: Driver substrate; A plurality of bonding electrodes, wherein the bonding electrodes are arranged on a surface of one side of the driving substrate; The flexible buffer layer is arranged on the same side of the bonding electrodes on the driving substrate, and the flexible buffer layer covers each of the bonding electrodes.

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