Chip transfer method and display device

Abstract

The application provides a chip transfer method and a display device. The chip transfer method is applied to a light-emitting chip, and the chip transfer method comprises the following steps: generating a first light-emitting chip on a first substrate, the first light-emitting chip has a protective layer facing the first substrate, the first light-emitting chip is provided in multiple groups, each group of the first light-emitting chip has a spacing area, the spacing area is provided with a light-absorbing layer, and the light-absorbing layer and the protective layer are provided in the same layer; the first light-emitting chip is opposite to a driving backboard, the opposite surface of the driving backboard is provided with multiple groups of first welding points, the first light-emitting chip is butted with the first welding points, and each group of the first welding points is provided with a second welding point and a third welding point; laser irradiation is controlled to irradiate the first light-emitting chip, the first light-emitting chip is separated from the first substrate; and the light-absorbing layer between the first light-emitting chips is removed, so that the second welding point and the third welding point are exposed. The technical scheme of the application can weld light-emitting chips of different light-emitting types on the driving backboard.

Description

Technical Field

[0001] This application relates to the field of display driver technology, and in particular to a chip transfer method and a display device. Background Technology

[0002] Currently, a common method in display panel manufacturing is to fabricate light-emitting chips on a sapphire substrate, then directly bond these chips to a driver backplane to form a light-emitting device. Finally, a laser-based peeling process separates the sapphire substrate and the light-emitting chips. However, this method can lead to the solder joints on the driver backplane being pre-melted by the laser, affecting the bonding of other types of light-emitting chips and resulting in weak bonding of those chips. Therefore, this method can only be used to transfer and bond light-emitting chips of the same type. Summary of the Invention

[0003] One objective of this application is to provide a chip transfer method and a display device that can reduce the pre-melting of solder joints on the driver backplane by laser irradiation and can solder light-emitting chips of different light-emitting types on the driver backplane.

[0004] According to one aspect of this application, a chip transfer method is provided, the chip transfer method being applied to a light-emitting chip, the chip transfer method comprising:

[0005] A first light-emitting chip is formed on a first substrate. The first light-emitting chip has a protective layer facing the first substrate. Multiple groups of the first light-emitting chips are arranged. There is a gap between each group of the first light-emitting chips. A light-absorbing layer is arranged in the gap. The light-absorbing layer and the protective layer are arranged in the same layer.

[0006] The first light-emitting chip is placed opposite the driving backplate. The opposing surface of the driving backplate is provided with multiple sets of first welding points. The first light-emitting chip is connected to the first welding points. A second welding point and a third welding point are provided between each set of first welding points.

[0007] The laser is controlled to irradiate the first light-emitting chip, causing the first light-emitting chip to disconnect from the first substrate.

[0008] Remove the light-absorbing layer between the first light-emitting chips to expose the second and third solder joints.

[0009] In one aspect, the step of generating the first light-emitting chip on the first substrate includes:

[0010] A connection layer, a first electrode layer, a multiple quantum well, and a second electrode layer are sequentially disposed on a first substrate. The connection layer includes the protective layer and the light-absorbing layer disposed on the same layer.

[0011] The connecting layer, the first electrode layer, the multiple quantum wells, and the second electrode layer are etched to expose the light-absorbing layer and the first electrode layer. A first electrode is formed on the surface of the first electrode layer, and a second electrode layer is formed on the surface of the second electrode layer to generate the first light-emitting chip.

[0012] In one aspect, the step of etching the interconnect layer, the first electrode layer, the multiple quantum wells, and the second electrode layer further includes:

[0013] The light-absorbing layer is subjected to transition etching so that the thickness of the light-absorbing layer is less than the thickness of the protective layer.

[0014] In one aspect, the step of performing transition etching on the light-absorbing layer further includes:

[0015] A portion of the thickness of the light-absorbing layer is removed to form a thinning section, the thinning section being located near the side of the first light-emitting chip;

[0016] Wherein, the thickness of the thinning section is D1, the thickness of the light-absorbing layer is D2, and the thickness of the protective layer is D3, then the following condition is satisfied: D1 < D2 < D3.

[0017] In one aspect, the thickness of the thinned section is between 0.5 μm and 1.0 μm.

[0018] In one aspect, the thinning segment is disposed around the first light-emitting chip.

[0019] In one aspect, the step of removing the light-absorbing layer between the first light-emitting chips includes:

[0020] The light-absorbing layer located between the first light-emitting chips is bonded and peeled off using an adhesive-peel method.

[0021] In one aspect, the chip transfer method further includes:

[0022] A second light-emitting chip is formed on a second substrate. The second light-emitting chip adopts the transfer step of the first light-emitting chip. The second light-emitting chip is connected to a second solder joint. The height of the second light-emitting chip is greater than the height of the first light-emitting chip, or the thickness of the second solder joint is greater than the thickness of the first solder joint. The wavelengths of the light emitted by the first light-emitting chip and the second light-emitting chip are different.

[0023] In one aspect, the chip transfer method further includes:

[0024] A third light-emitting chip is formed on a third substrate. The third light-emitting chip adopts the transfer step of the first light-emitting chip. The third light-emitting chip is connected to the third bonding point. The height of the third light-emitting chip is greater than the height of the second light-emitting chip, or the thickness of the third bonding point is greater than the thickness of the second bonding point. The wavelengths of the light emitted by the first light-emitting chip, the second light-emitting chip, and the third light-emitting chip are all different.

[0025] In one aspect, the distance between the protective layer of the first light-emitting chip and the opposing surface of the driving backplate is H1, the distance between the protective layer of the second light-emitting chip and the opposing surface of the driving backplate is H2, the distance between the protective layer of the third light-emitting chip and the opposing surface of the driving backplate is H3, the height difference between H2 and H1 is d1, and the height difference between H3 and H2 is d2, then the following condition is met:

[0026] 1.0um≤d1≤2.5um, 1.0um≤d2≤2.5um.

[0027] In addition, to solve the above problems, this application also provides a display device, the display device including a driving backplate, the driving backplate having a display area and a non-display area, the non-display area surrounding the display area, the display device further including a light-emitting chip, the light-emitting chip being transferred to the display area of ​​the driving backplate using the chip transfer method described above, the non-display area being provided with a circuit board, the circuit board being used to supply power to the light-emitting chip.

[0028] In the technical solution of this application, when the first light-emitting chip is formed on the first substrate, a light-absorbing layer is provided in the spacer area between each group of light-emitting chips. After the first light-emitting chip is placed on the first bonding point of the driving backplate, when the first light-emitting chip and the first substrate are separated by laser irradiation, the light-absorbing layer between each group of first light-emitting chips can absorb the laser, preventing the laser from directly irradiating the driving backplate, thereby protecting the second and third bonding points on the driving backplate and preventing the bonding points from melting due to light irradiation. After the first light-emitting chip and the first substrate are completely separated, the light-absorbing layer between each group of first light-emitting chips is peeled off, exposing the second and third bonding points, which facilitates the placement of other types of light-emitting chips.

[0029] Thus, this solution protects the remaining solder points on the driver backplane, facilitating the soldering of other types of light-emitting chips. Therefore, this technical solution can directly install different types of light-emitting chips while ensuring soldering strength.

[0030] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0031] The above and other objectives, features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0032] Figure 1 This is a flowchart of the first light-emitting chip transfer method according to the first embodiment of this application.

[0033] Figure 2 It is in this application Figure 1 A flowchart illustrating the process of generating the first light-emitting chip.

[0034] Figure 3 It is in this application Figure 2 A flowchart illustrating the etching process for generating the first light-emitting chip.

[0035] Figure 4 It is in this application Figure 1 A flowchart illustrating the process steps for stripping the light-emitting layer.

[0036] Figure 5 This is a flowchart of the second light-emitting chip transfer method in the first embodiment of this application.

[0037] Figure 6 This is a flowchart of the third light-emitting chip transfer method in the first embodiment of this application.

[0038] Figure 7 This application Figure 2 The corresponding structural diagram of step S101.

[0039] Figure 8 This application Figure 2 The corresponding structural diagram of step S102.

[0040] Figure 9 This application Figure 2 The corresponding structural diagram of step S101.

[0041] Figure 10 This application Figure 1 The corresponding structural diagram of the first light-emitting chip in the middle.

[0042] Figure 11 This application Figure 1 The corresponding structural diagram of step S120.

[0043] Figure 12 This application Figure 1 The corresponding structural diagram of step S130.

[0044] Figure 13 This is a structural diagram of the second and third light-emitting chips in this application.

[0045] Figure 14This is a structural diagram of the support layer provided at the second and third welding points in this application.

[0046] Figure 15 This is a schematic diagram of the display device according to the second embodiment of this application.

[0047] The annotations in the attached figures are explained as follows:

[0048] 10. First substrate; 20. First light-emitting chip; 30. Driving backplate; 40. Adhesive substrate; 50. Second light-emitting chip; 60. Third light-emitting chip; 70. Laser;

[0049] 201. Spacing area; 200. Connecting layer; 210. Protective layer; 211. Light-absorbing layer; 212. First electrode layer; 213. Multiple quantum wells; 214. Second electrode layer; 211a. Thinning section; 211b. Groove; 215. Conductive layer; 216. First electrode; 217. Second electrode; 310. First welding point; 320. Second welding point; 330. Third welding point; 340. Support layer; 301. Display area; 302. Non-display area; 410. Adhesive. Detailed Implementation

[0050] Although this application can be readily embodied in various forms of implementation, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of this application and is not intended to limit the application to what is described herein.

[0051] Therefore, a feature described in this specification is used to illustrate one feature of one embodiment of this application, and does not imply that every embodiment of this application must have the described feature. Furthermore, it should be noted that this specification describes many features. While certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0052] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of this application are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, these directional indications also change accordingly.

[0053] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided to make the description of this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0054] The preferred embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0055] Example 1

[0056] Currently, light-emitting chips are typically grown on a substrate, such as sapphire. Sapphire's main component is aluminum oxide, and it is transparent. After the grown chip is transferred to a driver backplane, it is peeled off from the sapphire substrate using laser irradiation. However, the laser can penetrate directly through the sapphire substrate and irradiate the driver backplane. The driver backplane has solder joints, which may melt, preventing the subsequent fixation of the chip. Furthermore, the driver backplane also has numerous circuits, which are easily damaged by the laser irradiation.

[0057] Therefore, this application provides a chip transfer method that can be used in LED (Light Emitting Diode) displays and OLED (Organic Light-Emitting Diode) displays.

[0058] See Figure 1 , Figure 10 , Figure 11 and Figure 12 As shown, a chip transfer method is applied to a light-emitting chip. The chip transfer method includes:

[0059] In step S100, a first light-emitting chip 20 is formed on the first substrate 10. The first light-emitting chip 20 has a protective layer 210 facing the first substrate 10. Multiple groups of the first light-emitting chips 20 are provided, with a spacing region 201 between each group. A light-absorbing layer 211 is disposed in the spacing region 201, and the light-absorbing layer 211 and the protective layer 210 are disposed on the same layer. The protective layer 210 is used to protect the internal structure of the first light-emitting chip 20, preventing adverse effects from the external environment, such as reducing burns from laser irradiation 70 and reducing oxygen penetration, thereby reducing oxidation. The light-absorbing layer 211 is used to absorb light, preventing light from directly irradiating the driving backplane 30 through the light-absorbing layer 211. The light-absorbing layer 211 and the protective layer 210 are made of the same material, such as gallium nitride or photosensitive resin.

[0060] In step S110, the first light-emitting chip 20 is positioned opposite the driving backplate 30. The opposing surface of the driving backplate 30 has multiple sets of first solder points 310. The first light-emitting chip 20 is connected to the first solder points 310. A second solder point 320 and a third solder point 330 are provided between each set of first solder points 310. During the alignment process, the first substrate 10 with the first light-emitting chip 20 is flipped onto the driving backplate 30. Two first solder points 310 are provided: one corresponds to the anode connection of the first light-emitting chip 20, and the other corresponds to the cathode connection of the first light-emitting chip 20. The first light-emitting chip 20 emits light by connecting the cathode and anode circuit.

[0061] In step S120, the laser 70 is controlled to irradiate the first light-emitting chip 20, causing the first light-emitting chip 20 to detach from the first substrate 10. A laser source is disposed on the side of the first substrate 10 away from the driving backplate 30. The laser 70 is emitted from the laser source towards the first substrate 10. After passing through the first substrate 10, the laser 70 contacts the protective layer 210 and the light-absorbing layer 211 respectively. The contact surfaces between the protective layer 210 and the light-absorbing layer 211 and the first substrate 10 begin to decompose. After decomposition, the protective layer 210 and the light-absorbing layer 211 detach from the first substrate 10. In this way, the first substrate 10 and the first light-emitting chip 20 can be separated.

[0062] In step S130, the light-absorbing layer 211 between the first light-emitting chips 20 is removed to expose the second welding point 320 and the third welding point 330. The laser irradiation time is short, only decomposing a small portion of the light-absorbing layer 211 and the protective layer 210. At this time, the light-absorbing layer 211 is still located above the second welding point 320 and the third welding point 330. That is, the light-absorbing layer 211 and the protective layer 210 are still connected. To facilitate subsequent welding of the second light-emitting chip 50 and the third light-emitting chip 60, the light-absorbing layer 211 between the first light-emitting chips 20 is removed. This exposes the positions of the second welding point 320 and the third welding point 330, allowing welding of either the second welding point 320 or the third welding point 330 to proceed.

[0063] In this embodiment, when the first light-emitting chip 20 is formed on the first substrate 10, a light-absorbing layer 211 is provided in the spacing region 201 between each group of light-emitting chips. After the first light-emitting chip 20 is placed on the first bonding point 310 of the driving backplate 30, when the first light-emitting chip 20 and the first substrate 10 are separated by laser 70, the light-absorbing layer 211 between each group of first light-emitting chips 20 can absorb the laser 70, preventing the laser 70 from directly irradiating the driving backplate 30, thereby protecting the second bonding point 320 and the third bonding point 330 on the driving backplate 30 and preventing the bonding points from melting due to light exposure. After the first light-emitting chip 20 and the first substrate 10 are separated, the light-absorbing layer 211 between each group of first light-emitting chips 20 is peeled off, exposing the second bonding point 320 and the third bonding point 330, which facilitates the setting of other types of light-emitting chips.

[0064] Thus, this solution protects the remaining solder points on the driver backplane 30, facilitating the soldering of other types of light-emitting chips. Therefore, this technical solution can directly install different types of light-emitting chips while ensuring soldering strength.

[0065] See Figure 2 , Figure 7 , Figure 8 As shown, the steps for forming the first light-emitting chip 20 on the first substrate 10 in order to protect the second solder joint 320 and the third solder joint 330 include:

[0066] In step S101, a connection layer 200, a first electrode layer 212, a multiple quantum well 213, and a second electrode layer 214 are sequentially disposed on the first substrate 10. The connection layer 200 includes a protective layer 210 and a light-absorbing layer 211 disposed on the same layer. The protective layer 210 and the light-absorbing layer 211 can be understood as the same layer, that is, the protective layer 210 and the light-absorbing layer 211 are disposed on the first substrate 10 through the same printing process or coating process. The connection layer 200 is gallium nitride or photosensitive resin adhesive. When the connection layer 200 is gallium nitride, it is undoped gallium nitride, i.e., U-GaN. After the connection layer 200 is disposed, the first electrode layer 212, the multiple quantum well 213, and the second electrode layer 214 are sequentially disposed on the surface of the connection layer 200 facing away from the first substrate 10. The first electrode layer 212 can be either N-GaN or P-GaN, and the second electrode layer 214 is the remaining one. For example, if the first electrode layer 212 is N-GaN, then the second electrode layer 214 is P-GaN. If the second electrode layer 214 is N-GaN, then the first electrode layer 212 is P-GaN.

[0067] In step S102, the connection layer 200, the first electrode layer 212, the multiple quantum wells 213 and the second electrode layer 214 are etched to expose the light-absorbing layer 211 and the first electrode layer 212. A first electrode 216 is formed on the surface of the first electrode layer 212 and a second electrode layer 214 is formed on the surface of the second electrode layer 214 to generate the first light-emitting chip 20.

[0068] Specifically, dry etching can be used. Dry etching typically refers to an etching technique that uses glow discharge to generate plasma containing charged particles such as ions and electrons, as well as highly chemically active neutral atoms, molecules, and free radicals, for pattern transfer. By exposing the light-absorbing layer 211, the first electrode layer 212, the multiple quantum wells 213, and the second electrode layer 214 are divided into multiple independent epitaxial layers.

[0069] By exposing the first electrode layer 212, a first electrode 216 can be disposed on the first electrode layer 212. The second electrode layer 214 and the multiple quantum wells 213 are partially etched away, while other portions are retained. A conductive layer 215 is disposed on the surface of the retained second electrode layer 214, and a second electrode 217 is disposed on the conductive layer 215. The conductive layer 215 can be indium tin oxide, such as ITO (indium tin oxide).

[0070] The first electrode 216 and the second electrode 217 are respectively anode and cathode. When the first light-emitting chip 20 is placed on the driving backplate 30, the first electrode 216 is connected to one of the first solder joints 310, and the second electrode 217 is connected to the other first solder joint 310.

[0071] See Figure 2 and Figure 8 As shown, the step of etching the interconnect layer 200, the first electrode layer 212, the multiple quantum wells 213, and the second electrode layer 214 further includes:

[0072] In step S103, a transition etching is performed on the light-absorbing layer 211 to make its thickness less than that of the protective layer 210. The transition etching ensures that the light-absorbing layer 211 is fully exposed. Originally, the light-absorbing layer 211 and the protective layer 210 were disposed on the same layer and had the same thickness. After the transition etching, the thickness of the light-absorbing layer 211 becomes thinner. Therefore, the thickness of the light-absorbing layer 211 is less than that of the protective layer 210.

[0073] See Figure 3 and Figure 9 As shown, in order to facilitate the removal of the light-absorbing layer 211 from the first light-emitting chip 20, the step of performing transition etching on the light-absorbing layer 211 further includes:

[0074] Step S104: Remove a portion of the thickness of the light-absorbing layer 211 to form a thinned section 211a. The thinned section 211a is located close to the first light-emitting chip 20. To make the sidewalls of the first light-emitting chip 20 more uniform, the thinned section 211a is positioned close to the first light-emitting chip 20. The step of forming the thinned section 211a can be completed simultaneously with the transition etching step. When setting the thinned section 211a, a groove 211b can be etched at the corresponding position to form the thinned section 211a. The width of the corresponding groove 211b can be between 0.2-0.7 μm, for example, 0.5 μm.

[0075] In this context, the thickness of the thinning section 211a is D1, the thickness of the light-absorbing layer 211 is D2, and the thickness of the protective layer 210 is D3, satisfying the condition: D1 < D2 < D3. That is, the thinning section 211a has the smallest thickness. When the light-absorbing layer 211 is peeled off, the adhesive force will be concentrated at the thinning section 211a, causing the light-absorbing layer 211 to break at that location, thus detaching the light-absorbing layer 211 from the protective layer 210.

[0076] See Figure 4 and Figure 12 As shown, the step of removing the light-absorbing layer 211 between the first light-emitting chips 20 includes:

[0077] In step S131, the light-absorbing layer 211 located between the first light-emitting chips 20 is peeled off using an adhesive peeling method. The adhesive peeling method results in a simple adhesive structure that is easy to operate. During the peeling operation, adhesive 410 can be applied to the surface of an adhesive substrate 40. The adhesive substrate 40 is positioned close to the first light-emitting chip 20, and the adhesive 410 is bonded to the light-absorbing layer 211. Then, the adhesive substrate 40 is moved away from the first light-emitting chip 20 along a predetermined path, thereby peeling off the light-absorbing layer 211 and allowing it to adhere to the adhesive on the adhesive substrate 40.

[0078] Furthermore, in order to ensure that the light-absorbing layer 211 can be peeled off, the adhesive force for peeling off the light-absorbing layer 211 located in the spacer region 201 is F1, the welding adhesive force between the first light-emitting chip 20 and the corresponding welding point is F2, and the force required to disconnect the light-absorbing layer 211 in the spacer region 201 is F3, then the following conditions are met: F3 < F1 < F2.

[0079] To ensure the smooth peeling of the light-absorbing layer 211, and to prevent the laser 70 from projecting onto the light-absorbing layer 211, the thickness of the thinning section 211a is between 0.5µm and 1.0µm. If the thickness of the thinning section 211a is less than 0.5µm, it is too thin and will easily decompose under the irradiation of the laser 70, creating a gap between the light-absorbing layer 211 and the protective layer 210. The laser 70 will then irradiate the drive backplate 30 through this gap. Therefore, the thickness of the thinning section 211a is controlled to be greater than 0.5µm. If the thickness of the thinning section 211a is greater than 1.0µm, it is too thick, resulting in an overly strong bond between the protective layer 210 and the light-absorbing layer 211, making it difficult to quickly peel off the light-absorbing layer 211.

[0080] Furthermore, in order to allow each first light-emitting chip 20 to be set independently, the thinning section 211a is set around the first light-emitting chip 20. After the bonding operation is performed, a certain area is spaced around each first light-emitting chip 20.

[0081] See Figure 5 , Figure 13 and Figure 14 As shown, this implementation scheme can incorporate other types of light-emitting chips. The chip transfer method also includes:

[0082] A second light-emitting chip 50 is formed on a second substrate. The second light-emitting chip 50 adopts the same transfer step as the first light-emitting chip 20. The second light-emitting chip 50 is mated with a second bonding point 320. The height of the second light-emitting chip 50 is greater than the height of the first light-emitting chip 20, or the thickness of the second bonding point 320 is greater than the thickness of the first bonding point 310. The wavelengths of the light emitted by the first light-emitting chip 20 and the second light-emitting chip 50 are different. The second substrate can also be a sapphire substrate.

[0083] Specifically, in step S200, a second light-emitting chip 50 is formed on the second substrate. The second light-emitting chip 50 has a protective layer 210 facing the second substrate. Multiple groups of second light-emitting chips 50 are provided, with a spacing region 201 between each group. A light-absorbing layer 211 is disposed in the spacing region 201, and the light-absorbing layer 211 and the protective layer 210 are disposed on the same layer. The protective layer 210 is used to protect the internal structure of the second light-emitting chip 50, preventing adverse effects from the external environment, such as reducing burns from laser irradiation 70 and reducing oxygen penetration, thereby reducing oxidation. The light-absorbing layer 211 is used to absorb light, preventing light from directly irradiating the driving backplane 30 through the light-absorbing layer 211. The light-absorbing layer 211 and the protective layer 210 are made of the same material, such as gallium nitride or photosensitive resin.

[0084] In step S210, the second light-emitting chip 50 is positioned opposite the driving backplate 30. The opposing surface of the driving backplate 30 has multiple sets of second solder points 320. The second light-emitting chip 50 is connected to the second solder points 320. The thickness of the second light-emitting chip 50 is greater than the thickness of the first light-emitting chip 20, or the thickness of the solder points corresponding to the second light-emitting chip 50 is greater than the thickness of the corresponding solder points of the first light-emitting chip 20. To prevent the second substrate or adhesive substrate 40 from touching the protective layer 210 of the first light-emitting chip 20 during the placement of the second light-emitting chip 50, the thickness of the second light-emitting chip 50 is controlled to be greater than the thickness of the first light-emitting chip 20. For example, the lengths of the first electrode 216 and the second electrode 217 of the second light-emitting chip 50 are extended, thereby increasing the thickness of the second light-emitting chip 50.

[0085] Alternatively, the thickness of the solder joint corresponding to the second light-emitting chip 50 can be greater than the thickness of the solder joint corresponding to the first light-emitting chip 20. That is, the second solder joint 320 is higher than the first solder joint 310. For example, a support layer 340 can be provided between the position of the second solder joint 320 and the driving backplate 30, thereby raising the height of the second solder joint 320 to be greater than the height of the first solder joint 310.

[0086] In step S220, the laser 70 is controlled to irradiate the second light-emitting chip 50, causing the second light-emitting chip 50 to detach from the second substrate. A laser source is disposed on the side of the second substrate opposite to the driving backplate 30. The laser 70 is emitted from the laser source towards the second substrate. After passing through the second substrate, the laser 70 contacts the protective layer 210 and the light-absorbing layer 211. The contact surfaces of the protective layer 210 and the light-absorbing layer 211 with the second substrate begin to decompose, and after decomposition, the protective layer 210 and the light-absorbing layer 211 detach from the second substrate. In this way, the second substrate and the second light-emitting chip 50 can be separated.

[0087] Step S230: Remove the light-absorbing layer 211 between the second light-emitting chips 50 to expose the third welding point 330;

[0088] The irradiation time of laser 70 is short, only enough to decompose a small portion of the light-absorbing layer 211 and the protective layer 210. At this time, the light-absorbing layer 211 is still connected to the protective layer 210. To facilitate the subsequent welding of the third light-emitting chip 60, the light-absorbing layer 211 between the second light-emitting chips 50 is removed. In this way, the position of the third welding point 330 is exposed, and the welding of the third welding point 330 is then performed.

[0089] The first light-emitting chip 20 is one of a blue light-emitting diode, a green light-emitting diode, and a red light-emitting diode, and the second light-emitting chip 50 is one of the remaining two types of light-emitting diodes.

[0090] See Figure 6 , Figure 13 and Figure 14 As shown, in this embodiment, a third light-emitting chip 60 can also be formed on a third substrate. The third light-emitting chip 60 adopts the transfer step of the first light-emitting chip 20. The third light-emitting chip 60 is connected to a third bonding point 330. The height of the third light-emitting chip 60 is greater than the height of the second light-emitting chip 50, or the thickness of the third bonding point 330 is greater than the thickness of the second bonding point 320. The wavelengths of the light emitted by the first light-emitting chip 20, the second light-emitting chip 50, and the third light-emitting chip 60 are all different. The third substrate can also be a sapphire substrate.

[0091] Specifically, in step S300, a third light-emitting chip 60 is formed on a third substrate. The third light-emitting chip 60 has a protective layer 210 facing the third substrate. Multiple groups of third light-emitting chips 60 are provided, with a spacing region 201 between each group. A light-absorbing layer 211 is provided in the spacing region 201, and the light-absorbing layer 211 and the protective layer 210 are disposed on the same layer. The protective layer 210 is used to protect the internal structure of the third light-emitting chip 60, preventing adverse effects from the external environment, such as reducing burns from laser irradiation 70 and reducing oxygen penetration, thereby reducing oxidation. The light-absorbing layer 211 is used to absorb light, preventing light from directly irradiating the driving backplane 30 through the light-absorbing layer 211. The light-absorbing layer 211 and the protective layer 210 are made of the same material, such as gallium nitride or photosensitive resin.

[0092] In step S310, the third light-emitting chip 60 is positioned opposite the driving backplate 30. The opposing surface of the driving backplate 30 has multiple sets of third solder points 330. The third light-emitting chip 60 is connected to the third solder points 330. The thickness of the third light-emitting chip 60 is greater than the thickness of the second light-emitting chip 50, or the thickness of the solder points corresponding to the third light-emitting chip 60 is greater than the thickness of the corresponding solder points of the second light-emitting chip 50. To prevent the third substrate or adhesive substrate 40 from touching the protective layer 210 of the second light-emitting chip 50 during the placement of the third light-emitting chip 60, the thickness of the third light-emitting chip 60 is controlled to be greater than the thickness of the second light-emitting chip 50. For example, the lengths of the first electrode 216 and the second electrode 217 of the third light-emitting chip 60 are extended, thereby increasing the thickness of the third light-emitting chip 60.

[0093] Alternatively, the thickness of the solder joint corresponding to the third light-emitting chip 60 can be greater than the thickness of the solder joint corresponding to the second light-emitting chip 50. That is, the third solder joint 330 is higher than the second solder joint 320. For example, a support layer 340 can be provided between the position of the third solder joint 330 and the driving backplate 30, thereby raising the height of the third solder joint 330 to be greater than the height of the second solder joint 320.

[0094] In step S320, the laser 70 is controlled to irradiate the third light-emitting chip 60, causing the third light-emitting chip 60 to detach from the third substrate. A laser source is positioned on the side of the third substrate opposite to the driving backplate 30. The laser 70 is emitted from the laser source towards the third substrate. After passing through the third substrate, the laser 70 contacts the protective layer 210 and the light-absorbing layer 211. The contact surfaces between the protective layer 210 and the light-absorbing layer 211 and the third substrate begin to decompose, and after decomposition, the protective layer 210 and the light-absorbing layer 211 detach from the third substrate. In this way, the third substrate and the third light-emitting chip 60 can be separated.

[0095] Step S330: Remove the light-absorbing layer 211 of the third light-emitting chip 60. The irradiation time of the laser 70 is short, only a small portion of the light-absorbing layer 211 and the protective layer 210 can be decomposed. At this time, the light-absorbing layer 211 is still attached to the protective layer 210. The light-absorbing layer 211 between the third light-emitting chips 60 is removed by adhesive peeling.

[0096] In this design, the first light-emitting chip 20 is one of a blue, green, or red LED; the second light-emitting chip 50 is one of the remaining two types; and the third light-emitting chip 60 is the remaining type. It should be noted that when the light-emitting chip is a blue or green LED, the protective layer 210 is U-GaN. When the light-emitting chip is a red LED, the protective layer 210 is a photosensitive resin adhesive, such as BCB adhesive.

[0097] To reduce interference between different types of LEDs during installation, the distance between the protective layer 210 of the first LED 20 and the opposing surface of the driving backplate 30 is H1, the distance between the protective layer 210 of the second LED 50 and the opposing surface of the driving backplate 30 is H2, and the distance between the protective layer 210 of the third LED 60 and the opposing surface of the driving backplate 30 is H3. The height difference between H2 and H1 is d1, and the height difference between H3 and H2 is d2, satisfying: 1.0um ≤ d1 ≤ 2.5um, 1.0um ≤ d2 ≤ 2.5um. Controlling the height difference between 1.0um and 2.5um effectively avoids interference in transferring different types of LEDs and prevents the overall driving backplate 30 from becoming too thick.

[0098] Example 2

[0099] See Figure 15 As shown, this application also provides a display device, which includes a driving backplate 30. The driving backplate 30 has a display area 301 and a non-display area 302. The non-display area 302 surrounds the display area 301. The display device also includes a light-emitting chip. The light-emitting chip is transferred to the display area 301 of the driving backplate 30 by a chip transfer method. A circuit board is disposed in the non-display area 302. The circuit board is used to supply power to the light-emitting chip.

[0100] Chip transfer methods include:

[0101] A light-emitting chip is fabricated on a substrate. Each chip has a protective layer facing the substrate. Multiple groups of chips are arranged, with a spacer between each group. A light-absorbing layer is disposed in each spacer, and the light-absorbing layer and protective layer are disposed on the same layer. The protective layer protects the internal structure of the chip, preventing adverse effects from the external environment, such as reducing laser burns and oxygen infiltration, thereby minimizing oxidation. The light-absorbing layer absorbs light, preventing it from directly illuminating the driver backplane. The light-absorbing layer and protective layer are made of the same material, such as gallium nitride or photosensitive resin.

[0102] The LED chip is placed opposite the driver backplane. The opposing surface of the driver backplane has multiple sets of solder points. The LED chip is connected to these solder points, with other solder points between each set. During alignment, the substrate with the LED chip is flipped onto the driver backplane. There are two solder points: one corresponding to the anode of the LED chip, and the other to the cathode. Connecting the cathode and anode circuit enables the LED chip to emit light.

[0103] The system controls the laser to irradiate the light-emitting chip, causing the chip to detach from the substrate. A laser source is positioned on the side of the substrate away from the driving backplane. The laser beam is emitted from this source and, after passing through the substrate, contacts both the protective layer and the light-absorbing layer. The contact surfaces between the protective layer and the light-absorbing layer and the substrate begin to decompose, eventually detaching them from the substrate. This process allows the substrate and the light-emitting chip to be separated.

[0104] The light-absorbing layer between the light-emitting chips is removed to expose the solder joints. The laser irradiation time is short, only breaking down a small portion of the light-absorbing and protective layers; at this point, the light-absorbing layer is still above the other solder joints. In other words, the light-absorbing and protective layers are still connected. To facilitate subsequent soldering of the light-emitting chips and the substrate, the light-absorbing layer between the chips is removed. This exposes the locations of the other solder joints, allowing for the soldering of other types of light-emitting chips. The light-emitting chip can be one of a blue, green, or red LED.

[0105] Although this application has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since this application can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A chip transfer method, characterized in that, The chip transfer method is applied to a light-emitting chip, and the chip transfer method includes: A first light-emitting chip is formed on a first substrate. The first light-emitting chip has a protective layer facing the first substrate. Multiple groups of the first light-emitting chips are arranged. There is a gap region between each group of the first light-emitting chips. A light-absorbing layer is arranged in the gap region. The light-absorbing layer and the protective layer are arranged in the same layer. The light-absorbing layer and the protective layer are made of the same material. The material of the light-absorbing layer and the protective layer includes undoped gallium nitride. The first light-emitting chip is placed opposite the driving backplate. The opposing surface of the driving backplate is provided with multiple sets of first solder points. The first light-emitting chip is connected to the first solder points. A second solder point and a third solder point are provided between each set of first solder points. The light-absorbing layer can block the second solder point and the third solder point. The protective layer and the light-absorbing layer are irradiated with a laser, causing them to partially decompose, thereby detaching the first light-emitting chip and the light-absorbing layer from the first substrate. Remove the light-absorbing layer between the first light-emitting chips to expose the second and third solder joints.

2. The chip transfer method according to claim 1, characterized in that, The step of generating the first light-emitting chip on the first substrate includes: A connection layer, a first electrode layer, a multiple quantum well, and a second electrode layer are sequentially disposed on a first substrate. The connection layer includes the protective layer and the light-absorbing layer disposed on the same layer. The connecting layer, the first electrode layer, the multiple quantum wells, and the second electrode layer are etched to expose the light-absorbing layer and the first electrode layer. A first electrode is disposed on the surface of the first electrode layer, a conductive layer is disposed on the surface of the second electrode layer, and a second electrode is disposed on the conductive layer to generate the first light-emitting chip.

3. The chip transfer method according to claim 2, characterized in that, The step of etching the interconnect layer, the first electrode layer, the multiple quantum wells, and the second electrode layer further includes: The light-absorbing layer is subjected to transition etching so that the thickness of the light-absorbing layer is less than the thickness of the protective layer.

4. The chip transfer method according to claim 3, characterized in that, The step of performing transition etching on the light-absorbing layer further includes: A portion of the thickness of the light-absorbing layer is removed to form a thinning section, the thinning section being located near the side of the first light-emitting chip; Wherein, the thickness of the thinning section is D1, the thickness of the light-absorbing layer is D2, and the thickness of the protective layer is D3, then the following condition is satisfied: D1 < D2 < D3.

5. The chip transfer method according to claim 4, characterized in that, The thickness of the thinned section is between 0.5 micrometers and 1.0 micrometers.

6. The chip transfer method according to claim 4, characterized in that, The thinning section is arranged around the first light-emitting chip.

7. The chip transfer method according to claim 1, characterized in that, The step of removing the light-absorbing layer between the first light-emitting chips includes: The light-absorbing layer located between the first light-emitting chips is bonded and peeled off using an adhesive-peel method.

8. The chip transfer method according to any one of claims 1 to 7, characterized in that, The chip transfer method further includes: A second light-emitting chip is formed on a second substrate. The second light-emitting chip adopts the transfer step of the first light-emitting chip. The second light-emitting chip is connected to a second solder joint. The height of the second light-emitting chip is greater than the height of the first light-emitting chip, or the thickness of the second solder joint is greater than the thickness of the first solder joint. The wavelengths of the light emitted by the first light-emitting chip and the second light-emitting chip are different.

9. The chip transfer method according to claim 8, characterized in that, The chip transfer method further includes: A third light-emitting chip is formed on a third substrate. The third light-emitting chip adopts the transfer step of the first light-emitting chip. The third light-emitting chip is connected to the third bonding point. The height of the third light-emitting chip is greater than the height of the second light-emitting chip, or the thickness of the third bonding point is greater than the thickness of the second bonding point. The wavelengths of the light emitted by the first light-emitting chip, the second light-emitting chip, and the third light-emitting chip are all different.

10. The chip transfer method according to claim 9, characterized in that, The distance between the protective layer of the first light-emitting chip and the opposing surface of the driving backplate is H1, the distance between the protective layer of the second light-emitting chip and the opposing surface of the driving backplate is H2, the distance between the protective layer of the third light-emitting chip and the opposing surface of the driving backplate is H3, the height difference between H2 and H1 is d1, and the height difference between H3 and H2 is d2. Then, the following conditions are met: 1.0 micrometer ≤ d1 ≤ 2.5 micrometer, 1.0 micrometer ≤ d2 ≤ 2.5 micrometer.

11. A display device, the display device comprising a driving backplate, the driving backplate having a display area and a non-display area, the non-display area surrounding the display area, characterized in that, The display device further includes a light-emitting chip, which is transferred to the display area of ​​the driving backplane using the chip transfer method as described in any one of claims 1 to 10. The non-display area is provided with a circuit board, which is used to supply power to the light-emitting chip.

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