Method for manufacturing display device using light-emitting element and device for manufacturing same

Abstract

The present disclosure is applicable to a technical field related to display devices, and relates to, for example, a method for manufacturing a display device using a light-emitting element using a micro light-emitting diode (LED) and a device for manufacturing same. A method for manufacturing a display device according to one embodiment of the present disclosure may comprise the steps of: preparing an assembly in which a shock-absorbing layer is formed on a wiring substrate in which an electrode pad is formed; preparing a temporary substrate in which light-emitting elements having light-emitting grades assigned according to positions are arranged; positioning the temporary substrate on the assembly such that the light-emitting elements face the shock-absorbing layer; transferring the light-emitting elements onto the shock-absorbing layer according to the light-emitting grades; and bonding the light-emitting elements to the electrode pad.

Description

Manufacturing method for display device using light-emitting element and manufacturing device thereof

[0001] The present disclosure is applicable to a technical field related to display devices, and relates to a method for manufacturing a display device using a light-emitting element using a micro LED (Light Emitting Diode) and a manufacturing device thereof, for example.

[0002] Recently, display devices with superior characteristics, such as thinness and flexibility, are being developed in the display technology field. In contrast, the major displays currently commercialized are represented by LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode).

[0003] However, in the case of LCD, there are problems such as slow response time and difficulty in implementing flexibility, and in the case of OLED, there are problems such as short lifespan and poor mass production yield.

[0004] Meanwhile, a light-emitting diode (LED) is a semiconductor light-emitting device well known for converting electric current into light. Starting with the commercialization of a red LED using a GaAsP compound semiconductor in 1962, it has been used as a light source for display images in electronic devices including information and communication devices, along with a green LED of the GaP:N series. Therefore, a method for solving the above-mentioned problem by implementing a display using a semiconductor light-emitting device can be presented. The semiconductor light-emitting device has various advantages such as a long lifespan, low power consumption, excellent initial driving characteristics, and high vibration resistance compared to a filament-based light-emitting device.

[0005] The size of these semiconductor light-emitting devices has recently been reduced to tens of micrometers. Therefore, when implementing a display device using these small-sized semiconductor light-emitting devices, a very large number of these devices must be assembled onto the display device's wiring board.

[0006] However, during the assembly process of these light-emitting devices, precisely positioning numerous semiconductor light-emitting devices at desired locations on the wiring board presents a significant challenge. This challenge is becoming increasingly acute with the advent of high-resolution displays.

[0007] For example, the process of separating and transferring a semiconductor light-emitting element formed on a growth substrate by a laser lift-off process can significantly increase the number of transfers.

[0008] In addition, since this transfer process is carried out through contact between a semiconductor light-emitting element and a wiring substrate or temporary substrate, there may be various processes that need to be resolved, such as alignment problems and chip breakage problems.

[0009] Meanwhile, the process of transferring light emitting elements of the same grade provided on the blue tape by binning may take a long time because the spacing between the light emitting elements is likely to be uneven.

[0010] Therefore, a solution to these problems is required.

[0011] The technical problem to be solved by the present disclosure is to provide a method for manufacturing a display device using a light-emitting element, in which a light-emitting element positioned on a temporary substrate can be directly transferred onto a wiring substrate in a non-contact manner, and a manufacturing device therefor.

[0012] The present disclosure provides a method for manufacturing a display device using a light-emitting element capable of high-precision alignment of the light-emitting element during a transcription process, and a manufacturing device therefor.

[0013] The present disclosure provides a method for manufacturing a display device using a light-emitting element, in which the transfer process and electrical connection process of the light-emitting element are simple, thereby improving the yield, and a manufacturing device therefor.

[0014] The present disclosure provides a method for manufacturing a display device using a light-emitting element that can be used in a display device having any resolution regardless of the pixel pitch of the display, and a manufacturing device thereof.

[0015] The present disclosure provides a method for manufacturing a display device using a light-emitting element, which can absorb the impact of the light-emitting element during a non-contact transfer process, thereby preventing the light-emitting element from bouncing off, and also preventing damage to the light-emitting element due to the same, and a manufacturing device thereof.

[0016] This disclosure

[0017]

[0018] A method for manufacturing a display device according to one embodiment of the present disclosure may include the steps of: preparing an assembly having a shock absorbing layer formed on a wiring substrate having electrode pads formed thereon; preparing a temporary substrate having light emitting elements having light emitting grades assigned according to positions arranged thereon; positioning the temporary substrate on the assembly such that the light emitting elements face the shock absorbing layer; transferring the light emitting elements onto the shock absorbing layer according to the light emitting grades; and bonding the light emitting elements to the electrode pads.

[0019] A manufacturing device of a display device according to one embodiment of the present disclosure includes a laser that irradiates light toward an assembly having a shock-absorbing layer formed on a wiring substrate from one side of a temporary substrate on which light-emitting elements are arranged; a transport unit that transports the position of the laser or the wiring substrate; a processor that controls the transport unit; and a memory that stores element information including information on the light-emitting levels of the light-emitting elements and their positions on the temporary substrate, wherein the processor can control the irradiation position of the laser by operating the transport unit according to the element information stored in the memory.

[0020] According to one embodiment of the present disclosure, the following effects are achieved.

[0021] First, according to an embodiment of the present disclosure, a light-emitting element positioned on a temporary substrate can be directly transferred onto a wiring substrate. For example, the transfer process can be performed in a single transfer process in a so-called chip-on-wafer (COW) state, in which the light-emitting element is formed on a growth substrate.

[0022] Therefore, the process of electrically connecting the light-emitting element to the wiring board can be performed immediately thereafter.

[0023] Additionally, high-precision alignment of light-emitting elements can be achieved through this process.

[0024] Additionally, yields can be improved by simplifying the transfer and electrical connection processes of light-emitting elements. This can significantly reduce the manufacturing costs and production time of display devices.

[0025] This transfer process can be used in display devices with any resolution, regardless of the display's pixel pitch. The time at which the laser lift-off is performed can be controlled.

[0026] In addition, since the transcription process described above can be performed in a non-contact manner, the interaction between materials is minimized, enabling active response to improving mass production yield.

[0027] This transfer process is applicable to vertical, horizontal, and flip-chip light-emitting devices. Furthermore, as described above, red light-emitting devices can be attached to a substrate and transferred under the same conditions as green and blue light-emitting devices positioned on a growth substrate.

[0028] In addition, the impact of the light-emitting element is absorbed during the non-contact transfer process, preventing the light-emitting element from bouncing off and preventing damage to the light-emitting element caused by this.

[0029] According to the present disclosure, since chip information is stored in the processor or memory, the transfer unit can be operated at high speed by the processor, allowing the transcription process to proceed without interruption. Accordingly, the entire transcription process can be performed quickly.

[0030] According to an embodiment of the present disclosure, light emitting elements arranged at regular intervals can be transferred onto a wiring board without interruption by a remote process (e.g., a dropping process) according to chip information, so that the entire transfer process can be performed quickly.

[0031] Furthermore, according to another embodiment of the present disclosure, there are additional technical effects not mentioned herein. Those skilled in the art will understand the full scope of the specification and drawings.

[0032] FIGS. 1 to 6 are schematic diagrams showing a method for manufacturing a display device according to one embodiment of the present disclosure.

[0033] FIG. 7 is a flowchart showing a method for manufacturing a display device according to one embodiment of the present disclosure.

[0034] Figures 8 to 10 are schematic diagrams showing a method for manufacturing a display device according to a comparative example.

[0035] FIG. 11 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0036] FIG. 12 is a cross-sectional schematic diagram showing a transfer process of a second light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0037] FIG. 13 is a cross-sectional schematic diagram showing a transfer process of a third light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0038] Fig. 14 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the first embodiment of the present disclosure is completed.

[0039] FIG. 15 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0040] FIG. 16 is a cross-sectional schematic diagram showing a state in which assembly of a light-emitting element is completed by a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0041] Fig. 17 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0042] Fig. 18 is a cross-sectional schematic diagram showing a transfer process of a second light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0043] FIG. 19 is a cross-sectional schematic diagram showing a transfer process of a third light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0044] Fig. 20 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the second embodiment of the present disclosure is completed.

[0045] FIG. 21 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0046] Fig. 22 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0047] Fig. 23 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the third embodiment of the present disclosure is completed.

[0048] Fig. 24 is a cross-sectional schematic diagram showing the state in which the adhesive layer is positioned in the manufacturing method of the display device according to the third embodiment of the present disclosure.

[0049] Fig. 25 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0050] Fig. 26 is a cross-sectional schematic diagram showing a state in which assembly of a light-emitting element is completed by a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0051] FIG. 27 is a cross-sectional schematic diagram for explaining a transfer process of a light-emitting element in a method for manufacturing a display device according to one embodiment of the present disclosure.

[0052] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification by the attached drawings.

[0053] Furthermore, although each drawing is described for convenience of explanation, it is also within the scope of the present disclosure that a person skilled in the art may implement another embodiment by combining at least two or more drawings.

[0054] Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

[0055] The semiconductor light-emitting device mentioned in the specification includes LEDs, micro LEDs, etc., and may be used interchangeably.

[0056]

[0057] Figures 1 to 6 are schematic diagrams illustrating a method for manufacturing a display device according to one embodiment of the present disclosure. Figure 7 is a flowchart illustrating a method for manufacturing a display device according to one embodiment of the present disclosure.

[0058] Hereinafter, the entire manufacturing process of a display device according to one embodiment of the present disclosure will be described step by step with reference to FIGS. 1 to 6 and the corresponding FIG. 7.

[0059] Referring to FIGS. 1 to 5 and FIG. 7, a process (S20) of preparing a temporary substrate (200) on which light-emitting elements (310) having light-emitting grades assigned according to positions on a transfer substrate are arranged can be performed.

[0060] Among the multiple light emitting elements (310) arranged on the temporary substrate (200), each light emitting element (310) may be assigned a chip ID and a light emitting level.

[0061] Here, for example, the chip ID may be a number assigned to each individual light-emitting element (310). However, in addition to the number, various means such as a combination of symbols and numbers may be used as long as the ID can distinguish each individual light-emitting element (310).

[0062] Referring to FIG. 1, the luminescence grade can be determined by a lighting test on a growth substrate (350) on which light-emitting elements (310) are grown.

[0063] The light emitting grades of the light emitting elements (310) grown on the growth substrate (350) and separated at least partially may be different from each other.

[0064] Ideally, light-emitting devices (310) manufactured under the same conditions on the same growth substrate (350) can have the same light-emitting characteristics, but in reality, differences may occur in the light-emitting characteristics of the light-emitting devices (310).

[0065] For example, the light emitting characteristics of light emitting elements (310) grown in the central portion of the growth substrate (350) may be superior to the light emitting characteristics of light emitting elements (310) grown in the peripheral portion of the growth substrate (350).

[0066] Depending on the luminescence characteristics, individual light-emitting elements (310) may be assigned luminescence grades. For example, a light-emitting element (310) having a certain level of luminescence characteristics may be assigned an A grade, and a light-emitting element (310) having a lower level of luminescence characteristics may be assigned a B grade. Meanwhile, a light-emitting element (310) having a lower level of luminescence characteristics than a light-emitting element (310) assigned a B grade may be assigned a C grade. Other detailed grades may also be assigned to the light-emitting elements (310). In this way, at least two luminescence grades may be assigned to individual light-emitting elements (310) depending on the luminescence characteristics.

[0067] If light-emitting elements (310) having the same light-emitting level are limitedly arranged in a certain area of ​​the display device, the light-emitting uniformity of the display device may be reduced.

[0068] Therefore, when manufacturing a display device using light-emitting elements (310) having different light-emitting grades, it may be advantageous to evenly distribute the light-emitting elements (310) having the same light-emitting grade over the entire area of ​​the display device. For example, the light-emitting elements (310) having the same light-emitting grade may be randomly distributed over the entire area of ​​the display device.

[0069] In this way, individual light-emitting elements (310) that are assigned a light-emitting grade according to their light-emitting characteristics can be stored together with the corresponding light-emitting grade and position information on the growth substrate. A chip ID can be assigned to each individual light-emitting element (310). The chip ID, light-emitting grade, and position information of the light-emitting element (310) can be stored in a processor (630; see FIG. 6) that later performs a process of transferring the light-emitting element (310). Meanwhile, the chip ID, light-emitting grade, and position information of the light-emitting element (310) can also be stored in a memory (640; see FIG. 6) connected to the processor (630). This memory (640) can be built into the processor (630) or can be separately provided externally.

[0070] Hereinafter, the chip ID, light emission level, and position information of the light emitting element (310) will be referred to as chip information of the light emitting element (310). Here, the position information may be coordinate information on the plane of the light emitting element (310). For example, the position information may include (x, y) coordinate values ​​for a reference point set on the growth substrate (350).

[0071] Meanwhile, in addition to the chip ID, light emission level, and location information, additional information may be provided to the light emitting element (310). For example, color coordinate information for the light emitting element (310), information indicating the degree of change in color coordinates according to temperature, etc. may be provided to each light emitting element (310).

[0072] In this way, with chip information assigned to each light-emitting element (310) and stored through a lighting test, referring to FIG. 2, the light-emitting element (310) can be transferred onto a temporary substrate (200).

[0073] The temporary substrate (200) may include an expansion tape (210). The temporary substrate (200) may be, for example, a glass substrate. The expansion tape (210) may be positioned on the temporary substrate (200). The expansion tape (210) may be removed during the subsequent process of transferring the light-emitting element (310) to the wiring substrate (100). Accordingly, the expansion tape (210) may be referred to as a sacrificial layer. Hereinafter, the terms expansion tape (210) and sacrificial layer (210) will be used interchangeably in the description.

[0074] The light emitting element (310) may be transferred onto an expansion tape (210) positioned on a temporary substrate (200). At this time, for example, the light emitting element (310) may be in a state where at least a portion of the light emitting element is separated from the growth substrate (350). The light emitting element (310) may be transferred to the temporary substrate (200) while the growth substrate (350) is attached. For example, the light emitting element (310) may be in a state where the semiconductor layers for light emission are separated from each other but connected together to the growth substrate (350).

[0075] In this way, when the light emitting elements (310) are transferred onto the temporary substrate (200), the light emitting elements (310) can have the same arrangement as when grown on the growth substrate (350). That is, the light emitting elements (310) can have a state in which they are arranged on the temporary substrate (200) at regular intervals.

[0076] Referring to Fig. 3, a groove can be formed so that the light emitting elements (310) are separated while the light emitting elements (310) are transferred onto a temporary substrate (200). The process of forming the groove so that the light emitting elements (310) are separated can be performed by laser irradiation.

[0077] For example, the process of forming grooves so that the light emitting elements (310) are separated may correspond to a laser scribing process. Through this laser scribing process, grooves may be formed in at least a portion of the growth substrate (350) so that the growth substrate (350) can be separated by a small external force. For example, through this laser scribing process, individual light emitting elements (310) may be separated from each other by the expansion of the expansion tape (210).

[0078] As another example, the process of forming grooves so that the light-emitting elements (310) are separated may be a dicing process. This dicing process may be a process of completely separating the light-emitting elements (310). In this way, even when the light-emitting elements (310) are completely separated, they can maintain their aligned positions while attached to the expansion tape (210).

[0079] Thereafter, referring to FIG. 4, the expansion tape (210) may be expanded by irradiating heat or light. For example, the expansion tape (210) may be expanded in all directions on the temporary substrate (200). Accordingly, the light-emitting elements (310) attached to the expansion tape (210) may be completely separated and arranged at a certain distance from each other on the expansion tape (210).

[0080] Referring to FIG. 5, through this process, light-emitting elements (310) can be arranged at a certain interval on a temporary substrate (200) so that they can be transferred to a wiring substrate (100).

[0081] At this time, the light emitting element (310) can be arranged so that the first electrode (for example, the n-electrode) and the second electrode (for example, the p-electrode) face opposite sides of the temporary substrate (200).

[0082] Meanwhile, a protective cap (300) for protecting the light emitting element (310) may be positioned on the outer surface of the light emitting element (310). This protective cap (300) may be coated on the outer surface of the light emitting element (310) to prevent the light emitting element (310) from being damaged during the transfer process.

[0083] As described above, the step (S20) of preparing a temporary substrate may include a step of transferring light-emitting elements (310) grown on a growth substrate (350) onto an expansion tape (210) of a temporary substrate (200) and a step of forming grooves so that the light-emitting elements (310) are separated.

[0084] This can be performed in the process of preparing an assembly capable of manufacturing a display device by transferring a light-emitting element (310) placed on such a temporary substrate (200) (S10). This assembly can be provided with a shock-absorbing layer (150) on a wiring substrate (100).

[0085] The process (S10) for preparing an assembly having a shock-absorbing layer (150) may be performed independently from the process (S20) for preparing a temporary substrate. For example, the process (S20) for preparing a temporary substrate may be performed first, followed by the process (S10) for preparing an assembly having a shock-absorbing layer (150). As another example, the process (S10) for preparing an assembly having a shock-absorbing layer (150) may be performed first, followed by the process (S20) for preparing a temporary substrate, or the process (S10) for preparing an assembly having a shock-absorbing layer (150) and the process (S20) for preparing a temporary substrate may be performed simultaneously.

[0086] Next, referring to FIGS. 6 and 7, a temporary substrate (200) may be positioned on an assembly provided with a shock-absorbing layer (150) (S30). That is, the light-emitting element (310) arranged on the temporary substrate (200) may be positioned so as to face the shock-absorbing layer (150). At this time, a certain distance may be maintained between the temporary substrate (200) and the shock-absorbing layer (150). For example, the temporary substrate (200) and the assembly may be positioned so that the light-emitting element (310) may fall onto the shock-absorbing layer (150) when separated from the expansion tape (210).

[0087] Thereafter, a process (S40) of transferring the light-emitting element (310) onto the shock-absorbing layer (150) according to the light-emitting grade may be performed. This process (S40) of transferring the light-emitting element (310) onto the shock-absorbing layer (150) according to the light-emitting grade may be performed by laser irradiation.

[0088] For example, after positioning the laser (610) at the location of the light-emitting element (310) having the corresponding light-emitting grade, the laser (610) can be irradiated to the light-emitting element (310). At this time, the light-emitting element (310) can be separated from the expansion tape (210) and placed on the shock-absorbing layer (150).

[0089] Specifically, the processor (630) can control the transfer unit (620) so that light-emitting elements (310) having a set light emission level are randomly arranged on the wiring board (100). At this time, as an example, the processor (630) can control the transfer unit (620) using chip information stored in the memory (640).

[0090] In this way, when the transfer unit (620) operates so that the light-emitting element (310) having the corresponding light-emitting grade is positioned at a set position of the wiring board (100), a laser (610) can be irradiated at the corresponding position to perform a transfer process.

[0091] This transcription process can be performed sequentially. Since the chip information is stored in the processor (630) or memory (640), the transfer unit (620) can be operated at high speed by the processor (630), allowing the transcription process to proceed without interruption. Therefore, the entire transcription process can be performed quickly.

[0092] For example, when using the so-called pick-and-place method, which involves picking up individual light-emitting elements and transferring them to the desired location on the wiring board, a lot of time may be required for the process of picking up the individual light-emitting elements, adjusting their location, and transferring them.

[0093] Meanwhile, since chip information for light-emitting elements is not included and binning is performed to transfer light-emitting elements of the same grade provided on the blue tape, the spacing between light-emitting elements is likely to be uneven, so the transfer process may take a long time.

[0094] However, according to the embodiment of the present disclosure, the light emitting elements (310) arranged at regular intervals can be transferred onto the wiring board (100) without interruption by a remote process (for example, a dropping process) according to chip information, so that the entire transfer process can be performed quickly.

[0095] Referring to FIG. 6, a manufacturing device (600) of a display device according to one embodiment of the present disclosure can continuously perform a process of remotely transferring light-emitting elements (310) arranged at regular intervals onto a wiring board (100) without interruption according to chip information.

[0096] Such a manufacturing device (600) may include a laser (610) that applies heat to a temporary substrate (200) to which a light-emitting element (310) is attached or an expansion tape (210) positioned on the temporary substrate (200) so that the light-emitting element (310) is separated from the expansion tape (or sacrificial layer; 210).

[0097] In addition, the manufacturing device (600) may include a transfer unit (620) that transfers the position of the laser (610) according to the position information of the light-emitting element (310). Meanwhile, it goes without saying that the transfer unit (620) may transfer the wiring board (100) according to the position information of the light-emitting element (310) while the position of the laser (610) is fixed.

[0098] This transport unit (620) can be controlled by a processor (630). Meanwhile, chip information of the light-emitting element (310) can be stored in a memory (640).

[0099] In this way, the manufacturing apparatus (600) of a display device according to one embodiment of the present disclosure may include a laser (610) that irradiates light toward an assembly on which a shock absorbing layer (210) is formed on a wiring substrate (100) from one side of a temporary substrate (200) on which light emitting elements (310) are arranged, a transport unit (620) that transports the position of the laser (610) or the wiring substrate (100), a processor (630) that controls the transport unit (620), and a memory (640) that stores element information including information on the light emitting levels of the light emitting elements (310) and their positions on the temporary substrate (200).

[0100] The processor (630) can control the irradiation position of the laser (610) by operating the transfer unit (620) according to the element information stored in the memory (640).

[0101]

[0102] Figures 8 to 10 are schematic diagrams showing a method for manufacturing a display device according to a comparative example.

[0103] As mentioned above, since chip information for the light emitting elements is not included and the process of transferring light emitting elements of the same grade provided on the blue tape by binning is performed, the spacing between the light emitting elements is likely to be uneven, so the transfer process may take a long time.

[0104] Referring to Fig. 8, similar to the process described above with reference to Fig. 1, light-emitting elements (31) are manufactured on a growth substrate (30) and lighting inspection can be performed in a state where they are separated from each other.

[0105] Through this lighting inspection process, the light emission grades of the light emitting elements (31) can be classified. This process of classifying the light emission grades can be called binning.

[0106] Referring to FIG. 9, light emitting elements (31) that are usually classified by grade can be provided in a state where light emitting elements (31) of the same grade are arranged on a blue tape (250).

[0107] For example, light emitting elements (31) of the same grade may be provided in a state in which they are individually transferred onto a blue tape (250). The blue tape (250) may be positioned on a transfer substrate (260).

[0108] In this way, since the light-emitting elements (31) arranged on the blue tape (250) are selectively transferred on the growth substrate (30) according to the light-emitting level, the spacing between the light-emitting elements (31) may not be constant. For example, the spacing between the light-emitting elements (31) may vary depending on the position on the blue tape (250) (a1, a2, a3, etc.).

[0109] Accordingly, in the process of transferring light emitting elements (31) having such irregular intervals onto a wiring board (100), a process of adjusting the position of the laser according to such irregular intervals may be added, which may delay the entire transfer process.

[0110] However, according to the embodiment of the present disclosure, the light emitting elements (310) arranged at regular intervals can be transferred onto the wiring board (100) without interruption by a remote process (for example, a dropping process) according to chip information, so that the entire transfer process can be performed quickly.

[0111]

[0112] Below, the process of transferring light-emitting elements onto the shock-absorbing layer according to the light-emitting grade and the process of bonding the light-emitting elements to the electrode pad are described step by step.

[0113] FIG. 11 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0114] Referring to FIG. 11, a process is illustrated in which an assembly of a wiring board (100) having a shock-absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light-emitting element (for example, a first light-emitting element (310)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light-emitting element (310) is transferred onto the shock-absorbing layer (150). Here, the base substrate (200) may be the same as the temporary substrate (200) described above. Hereinafter, the terms base substrate (200) and temporary substrate (200) are used interchangeably and explained. Meanwhile, in some cases, the base substrate (200) may mean a growth substrate.

[0115] By this process, the first light-emitting element (310) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner.

[0116] This type of non-contact transfer method may be a transfer method that is performed while maintaining a distance between the first light-emitting element (310) and the electrode pad (120).

[0117] At this time, the first light-emitting element (310) can be separated from the base substrate (200) by a laser lift off (LLO) method and transferred to the electrode pad (120) side.

[0118] That is, the process of transferring the first light-emitting element (310) onto the shock-absorbing layer (150) may include a step of irradiating the first light-emitting element (310) with a laser from the base substrate (200) side.

[0119] When a laser is irradiated to the first light-emitting element (310) from the base substrate (200) side, the interface between the base substrate (200) or the sacrificial layer (210) and the first light-emitting element (310) can be separated.

[0120] For example, when the base substrate (200) is a growth substrate of the first light-emitting element (310), the semiconductor material forming the first light-emitting element (310) may be decomposed so that the first light-emitting element (310) can be separated from the base substrate (200).

[0121] As another example, when the base substrate (200) is not a growth substrate of the first light-emitting element (310), a sacrificial layer (210) may be positioned between the base substrate (200) and the first light-emitting element (310). The first light-emitting element (310) may be attached to this sacrificial layer (210). When the first light-emitting element (310) is a red light-emitting element that emits red light, it may typically be grown on a gallium arsenide (GaAs) substrate. However, since the gallium arsenide substrate is not transparent to laser light, in this case, the first light-emitting element (310) may be separated from the growth substrate and attached to the sacrificial layer (210). Hereinafter, the case where the first light-emitting element (310) is a red light-emitting element will be described as an example.

[0122] In this way, the first light-emitting element (310) attached to the sacrificial layer (210) can be separated by irradiating the laser. That is, the first light-emitting element (310) attached to the sacrificial layer (210) can be separated by the laser lift-off method. At this time, the sacrificial layer (210) may include a material capable of absorbing laser light. For example, the sacrificial layer (210) may include a UV absorbing layer. For example, the sacrificial layer (210) may be formed as a UV absorbing layer.

[0123] At this time, the semiconductor material may be decomposed and gas may be generated. That is, gas may be locally generated between the first light-emitting element (310) and the base substrate (200) due to the laser lift-off process, and the first light-emitting element (310) may fall toward the electrode pad (120) with strong energy due to this gas. That is, the first light-emitting element (310) may fall at a speed greater than the speed generated by gravity.

[0124] The first light-emitting element (310) that falls with such strong energy reaches the shock-absorbing layer (150). At this time, the falling first light-emitting element (310) can be settled on the shock-absorbing layer (150) by having the shock absorbed by the shock-absorbing layer (150).

[0125] At this time, a protective cap (300) for protecting the first light-emitting element (310) may be positioned on the outer surface of the first light-emitting element (310). This protective cap (300) may be coated on the outer surface of the first light-emitting element (310) to prevent the first light-emitting element (310) from being damaged during the transfer process. Meanwhile, this protective cap (300) may also coat a conductive ball (400) for electrically connecting the first light-emitting element (310) to the electrode pad (120).

[0126] The shock absorbing layer (150) may include a nano-fiber layer. That is, the shock absorbing layer (150) may be formed of a nano-fiber layer. In addition, the shock absorbing layer (150) may have adhesiveness. Accordingly, the shock absorbing layer (150) may absorb the impact of the falling first light emitting element (310) and allow it to settle without bouncing off from the dropped position.

[0127] This shock absorbing layer (150) may be a fiber layer having nanometer-scale pores. For example, the size of the pores of the shock absorbing layer (150) may be approximately 60 to 80 nm.

[0128] An adhesive layer (140) may be positioned between the shock absorbing layer (150) and the electrode pad (120). Specifically, the adhesive layer (140) may be positioned between the shock absorbing layer (150) and the wiring board (100) having the electrode pad (120). For example, the shock absorbing layer (150) may be attached to the electrode pad (120) by the adhesive layer (140).

[0129] The shock-absorbing layer (150) and the adhesive layer (140) may have the same directional characteristics with respect to heat. For example, the shock-absorbing layer (150) and the adhesive layer (140) may have the same thermal characteristics, and when heat is applied, a reaction in the same direction may occur. For example, when heat is applied, both the shock-absorbing layer (150) and the adhesive layer (140) may be partially or completely liquefied and then hardened. In addition, the shock-absorbing layer (150) and the adhesive layer (140) may be hardened into a single layer when heat is applied.

[0130] Electrode pads (120) arranged on a wiring board (100) can be connected to signal electrodes (or data electrodes; not shown). These electrode pads (120) or signal electrodes can be connected to a TFT layer (130) equipped with a thin film transistor (TFT). A detailed description thereof is omitted.

[0131] As mentioned above, the first light-emitting element (310) can be electrically connected to the electrode pad (120) by a conductive ball (400). The conductive ball (400) can be transferred while attached to the first light-emitting element (310).

[0132] A plurality of first light-emitting elements (310) can be grown or attached to the base substrate (200). These first light-emitting elements (310) can be transferred to a predetermined location per pixel.

[0133] In Fig. 11, two pixels are illustrated, and a predetermined number of first light-emitting elements (310) can be transferred per pixel. For example, one first light-emitting element (310) can be transferred simultaneously per pixel. In Fig. 11, for convenience, a state in which the first light-emitting element (310) is transferred to one pixel is schematically illustrated, but the first light-emitting elements (310) can be transferred simultaneously to multiple pixels.

[0134]

[0135] FIG. 12 is a cross-sectional schematic diagram showing a transfer process of a second light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0136] Referring to FIG. 12, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a second light emitting element (320)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (320) is transferred onto the shock absorbing layer (150).

[0137] By this process, the second light emitting element (320) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner.

[0138] This type of non-contact transfer method may be a transfer method that is performed while maintaining a distance between the second light-emitting element (320) and the electrode pad (120).

[0139] At this time, the second light-emitting element (320) can be separated from the base substrate (200) by a laser lift off (LLO) method and transferred to the electrode pad (120) side.

[0140] That is, the process of transferring the second light-emitting element (320) onto the shock-absorbing layer (150) may include a step of irradiating the second light-emitting element (320) with a laser from the base substrate (200) side.

[0141] When a laser is irradiated to the second light-emitting element (320) from the base substrate (200) side, the interface between the base substrate (200) or the sacrificial layer (210) and the second light-emitting element (320) can be separated.

[0142] At this time, the second light-emitting element (320) may be a green light-emitting element (320) that emits green light. Hereinafter, the second light-emitting element (320) will be described as an example of a green light-emitting element.

[0143] For example, when the base substrate (200) is a growth substrate of a green light-emitting element (320), the semiconductor material (e.g., gallium nitride series semiconductor) forming the green light-emitting element (320) may be decomposed so that the green light-emitting element (320) can be separated from the base substrate (200).

[0144] At this time, the semiconductor material may be decomposed and gas may be generated. That is, gas (nitrogen gas) may be locally generated between the green light-emitting element (320) and the base substrate (200) due to the laser lift-off process, and the green light-emitting element (320) may fall toward the electrode pad (120) with strong energy due to this gas. That is, the green light-emitting element (320) may fall at a speed greater than the speed generated by gravity.

[0145] The green light-emitting element (320) falling with such strong energy reaches the shock-absorbing layer (150). At this time, the falling green light-emitting element (320) can be settled on the shock-absorbing layer (150) by having the shock absorbed by the shock-absorbing layer (150).

[0146] At this time, a protective cap (300) for protecting the green light-emitting element (320) may be positioned on the outer surface of the green light-emitting element (320). This protective cap (300) may be coated on the outer surface of the green light-emitting element (320) to prevent the green light-emitting element (320) from being damaged during the transfer process. Meanwhile, this protective cap (300) may also coat a conductive ball (400) for electrically connecting the green light-emitting element (320) to the electrode pad (120).

[0147] Other details may be the same as those described above with reference to Figure 11. Therefore, any duplicate explanations are omitted.

[0148] Referring to Fig. 12, the transfer process of the green light-emitting element (320) can be performed in a state where the red light-emitting element (310) is transferred onto the shock-absorbing layer (150) within one pixel. In this way, a predetermined number of green light-emitting elements (320) can be transferred per pixel in a state where the red light-emitting element (310) is transferred. In Fig. 12, for convenience, a state where the green light-emitting element (320) is transferred to one pixel is schematically illustrated, but the green light-emitting elements (320) can be transferred to multiple pixels simultaneously.

[0149]

[0150] FIG. 13 is a cross-sectional schematic diagram showing a transfer process of a third light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0151] Referring to FIG. 13, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a third light emitting element (330)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (330) is transferred onto the shock absorbing layer (150).

[0152] By this process, the third light-emitting element (330) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner.

[0153] This type of non-contact transfer method may be a transfer method that is performed while maintaining a distance between the third light-emitting element (330) and the electrode pad (120).

[0154] At this time, the third light-emitting element (330) can be separated from the base substrate (200) by a laser lift off (LLO) method and transferred to the electrode pad (120) side.

[0155] That is, the process of transferring the third light-emitting element (330) onto the shock-absorbing layer (150) may include a step of irradiating the third light-emitting element (330) with a laser from the base substrate (200) side.

[0156] When a laser is irradiated to the third light-emitting element (330) from the base substrate (200) side, the interface between the base substrate (200) or the sacrificial layer (210) and the third light-emitting element (330) can be separated.

[0157] At this time, the third light-emitting element (330) may be a blue light-emitting element (330) that emits blue light. Hereinafter, the third light-emitting element (330) will be described as an example of a blue light-emitting element.

[0158] For example, when the base substrate (200) is a growth substrate of a blue light-emitting element (330), the semiconductor material (e.g., gallium nitride series semiconductor) forming the blue light-emitting element (330) may be decomposed so that the blue light-emitting element (330) can be separated from the base substrate (200).

[0159] The blue light-emitting element (330) that is separated from the base substrate (200) by laser lift-off and falls with strong energy reaches the shock-absorbing layer (150). At this time, the falling blue light-emitting element (330) can be settled on the shock-absorbing layer (150) by having the shock absorbed by the shock-absorbing layer (150).

[0160] At this time, a protective cap (300) for protecting the blue light-emitting element (330) may be positioned on the outer surface of the blue light-emitting element (330). This protective cap (300) may be coated on the outer surface of the blue light-emitting element (330) to prevent the blue light-emitting element (330) from being damaged during the transfer process. Meanwhile, this protective cap (300) may also coat a conductive ball (400) for electrically connecting the blue light-emitting element (330) to the electrode pad (120).

[0161] Other details may be the same as those described above with reference to Figures 11 and 12. Therefore, any duplicate description will be omitted.

[0162] Referring to FIG. 13, a transfer process of a blue light-emitting element (330) can be performed in a state where a red light-emitting element (310) and a green light-emitting element (320) are transferred onto a shock-absorbing layer (150) within one pixel. In this way, a predetermined number of blue light-emitting elements (330) can be transferred per pixel in a state where the red light-emitting element (310) and the green light-emitting element (320) are transferred. In FIG. 13, for convenience, a state where a blue light-emitting element (330) is transferred to one pixel is schematically illustrated, but the blue light-emitting elements (330) can be transferred to multiple pixels simultaneously.

[0163]

[0164] Fig. 14 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the first embodiment of the present disclosure is completed.

[0165] By the process described with reference to FIGS. 11 to 13, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) within each pixel can be transferred onto the shock-absorbing layer (150).

[0166] Referring to Fig. 14, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are shown transferred and attached to a shock-absorbing layer (150).

[0167] At this time, the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) may be positioned on the shock-absorbing layer (150) with conductive balls (400) attached to their lower surfaces. Although not shown, the conductive balls (400) may be attached to the first electrodes (for example, P-type electrodes) of the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330).

[0168]

[0169] FIG. 15 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0170] In a state where a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are transferred onto the shock-absorbing layer (150) within each pixel, a process of bonding the light-emitting elements (310, 320, 330) to the electrode pad (120) can be performed.

[0171] Referring to Fig. 15, heat can be applied while the pressing part (500) is positioned on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) to bond the light-emitting elements (310, 320, 330) to the electrode pad (120).

[0172] That is, heat can be applied simultaneously while applying pressure to the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) using the compression unit (500).

[0173] By this process, the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) can be electrically connected to the electrode pad (120) by the conductive ball (400).

[0174] In this embodiment, a process of electrically connecting light-emitting elements (310, 320, 330) to electrode pads (120) by conductive balls (400) is described. However, it is to be understood that light-emitting elements (310, 320, 330) may be electrically connected to electrode pads (120) by electrical connection means other than conductive balls (400). For example, light-emitting elements (310, 320, 330) may be electrically connected to electrode pads (120) by conductive paste, solder, etc.

[0175]

[0176] FIG. 16 is a cross-sectional schematic diagram showing a state in which assembly of a light-emitting element is completed by a method for manufacturing a display device according to the first embodiment of the present disclosure.

[0177] As described above, when heat is applied while the pressing part (500) is positioned on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) to bond the light-emitting elements (310, 320, 330) to the electrode pad (120), a state as shown in FIG. 16 can be achieved.

[0178] Electrode pads (120) arranged on a wiring board (100) can be connected to signal electrodes (or data electrodes; not shown). These electrode pads (120) or signal electrodes can be connected to a TFT layer (130) equipped with a thin film transistor (TFT). Accordingly, each light emitting element (310, 320, 330) can be driven by switching driving by the TFT layer (130).

[0179] For example, when the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) are vertical light-emitting elements, a scan electrode (or common electrode; not shown) may be formed on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330).

[0180] As described above, since the shock-absorbing layer (150) and the adhesive layer (140) may have the same directional characteristics with respect to heat, after this bonding process, the shock-absorbing layer (150) and the adhesive layer (140) may be cured into a single layer (140) when heat is applied. That is, the layer referenced as 140 in FIG. 6 may mean a layer that is formed by combining the adhesive layer (140) and the shock-absorbing layer (150) while they are cured. However, in some cases, a portion of the shock-absorbing layer (150) may remain.

[0181]

[0182] Fig. 17 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0183] Referring to FIG. 17, according to the second embodiment, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a first light emitting element (310)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (310) is transferred onto the shock absorbing layer (150).

[0184] Through this process, the first light-emitting element (310) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner. This non-contact transfer method may be a transfer method that is performed while maintaining a distance between the first light-emitting element (310) and the electrode pad (120).

[0185] When a laser is irradiated to the first light-emitting element (310) from the base substrate (200) side, the interface between the base substrate (200) or the sacrificial layer (210) and the first light-emitting element (310) can be separated.

[0186] If the first light-emitting element (310) is a red light-emitting element that emits red light, it can usually be grown on a gallium arsenide (GaAs) substrate. However, since the gallium arsenide substrate is not transparent to laser light, in this case, the first light-emitting element (310) can be separated from the growth substrate and attached to the sacrificial layer (210). Hereinafter, the case where the first light-emitting element (310) is a red light-emitting element will be described as an example.

[0187] At this time, a protective cap (300) for protecting the red light-emitting element (310) may be positioned on the outer surface of the red light-emitting element (310). This protective cap (300) may be coated on the outer surface of the red light-emitting element (310) to prevent the red light-emitting element (310) from being damaged during the transfer process.

[0188] Electrode pads (120) arranged on a wiring board (100) can be connected to signal electrodes (or data electrodes; not shown). These electrode pads (120) or signal electrodes can be connected to a TFT layer (130) equipped with a thin film transistor (TFT).

[0189] In the present embodiment, a conductive ball (400) may be positioned on the electrode pad (120) to electrically connect the red light-emitting element (310) to the electrode pad (120). That is, unlike the first embodiment in which the conductive ball (400) is attached to the red light-emitting element (310) together with the protective cap (300), in the second embodiment, the conductive ball (400) may be positioned while being fixed on the electrode pad (120).

[0190] These conductive balls (400) can be fixed on the electrode pads (120) by an adhesive layer (140), and can also be fixed on the electrode pads (120) by a separate layer such as a paste or a photoresist. In addition, a conductive adhesive layer may be used instead of the conductive balls (400). For example, the conductive adhesive layer may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, etc. The conductive adhesive layer may be configured as a layer that allows electrical interconnection in the Z direction that penetrates the thickness, but has electrical insulation in the horizontal XY direction. Therefore, the conductive adhesive layer may be referred to as a Z-axis conductive layer.

[0191] An anisotropic conductive film is a film in which an anisotropic conductive medium is mixed with an insulating base material, and when heat and / or pressure are applied, only a specific portion becomes conductive due to the anisotropic conductive medium. Hereinafter, the anisotropic conductive film is described as being subjected to heat and / or pressure, but other methods may be applied to partially make the anisotropic conductive film conductive. The other methods described above may include, for example, applying only one of heat and / or pressure, or UV curing.

[0192] In addition, the anisotropic conductive medium can be, for example, conductive balls or conductive particles. For example, an anisotropic conductive film is a film in which conductive balls are mixed with an insulating base member, and when heat and / or pressure are applied, only a specific portion becomes conductive due to the conductive balls. An anisotropic conductive film can be a state containing a plurality of particles in which a core of a conductive material is covered by an insulating film made of a polymer material, and in this case, a portion to which heat and pressure are applied becomes conductive due to the core as the insulating film is destroyed. At this time, the shape of the core can be deformed to form a layer that contacts each other in the thickness direction of the film. As a more specific example, heat and pressure are applied to the entire anisotropic conductive film, and an electrical connection in the Z-direction is partially formed due to the height difference of the counterpart to which the anisotropic conductive film is adhered.

[0193] As another example, an anisotropic conductive film may contain a plurality of particles coated with a conductive material on an insulating core. In this case, the conductive material deforms (sticks together) in the area where heat and pressure are applied, thereby providing conductivity in the thickness direction of the film. As another example, a conductive material may penetrate the insulating base member in the Z-axis direction, thereby providing conductivity in the thickness direction of the film. In this case, the conductive material may have pointed ends.

[0194] The anisotropic conductive film may be a fixed array anisotropic conductive film (ACF) configured with conductive balls inserted into one surface of an insulating base member. More specifically, the insulating base member is formed of an adhesive material, the conductive balls are concentratedly arranged on the bottom portion of the insulating base member, and when heat or pressure is applied to the base member, the conductive balls deform together with the conductive balls, thereby becoming conductive in the vertical direction.

[0195] However, the present disclosure is not necessarily limited thereto, and the anisotropic conductive film may be formed in a form in which conductive balls are randomly mixed into an insulating base member, or in a form in which conductive balls are arranged in one of the layers (double-ACF).

[0196] Anisotropic conductive paste is a combination of paste and conductive balls. It can be a paste in which conductive balls are mixed with an insulating and adhesive base material. Furthermore, the solution containing conductive particles can be a solution containing conductive particles or nanoparticles.

[0197] This embodiment may be identical to the first embodiment described above except for the location of the challenge ball (400). Therefore, redundant descriptions are omitted.

[0198]

[0199] Fig. 18 is a cross-sectional schematic diagram showing a transfer process of a second light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0200] Referring to FIG. 18, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a second light emitting element (320)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (320) is transferred onto the shock absorbing layer (150).

[0201] Through this process, the second light-emitting element (320) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner. This non-contact transfer method may be a transfer method that is performed while maintaining a distance between the second light-emitting element (320) and the electrode pad (120).

[0202] The process of transferring the second light-emitting element (320) onto the shock-absorbing layer (150) may include a step of irradiating the second light-emitting element (320) with a laser from the base substrate (200) side.

[0203] When a laser is irradiated to the second light-emitting element (320) from the base substrate (200) side, the interface between the base substrate (200) and the second light-emitting element (320) can be separated.

[0204] At this time, the second light-emitting element (320) may be a green light-emitting element (320) that emits green light. Hereinafter, the second light-emitting element (320) will be described as an example of a green light-emitting element.

[0205] At this time, a protective cap (300) for protecting the green light-emitting element (320) may be positioned on the outer surface of the green light-emitting element (320). This protective cap (300) may be coated on the outer surface of the green light-emitting element (320) to prevent the green light-emitting element (320) from being damaged during the transfer process.

[0206] In the present embodiment, a conductive ball (400) may be positioned on the electrode pad (120) to electrically connect the green light-emitting element (320) to the electrode pad (120). That is, unlike the first embodiment in which the conductive ball (400) is attached to the green light-emitting element (320) together with the protective cap (300), in the second embodiment, the conductive ball (400) may be positioned while being fixed on the electrode pad (120).

[0207] These conductive balls (400) can be fixed on the electrode pads (120) by an adhesive layer (140), and can also be fixed on the electrode pads (120) by a separate layer such as paste or photoresist. In addition, a conductive adhesive layer may be used instead of the conductive balls (400). For example, the conductive adhesive layer may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, etc. The conductive adhesive layer may be configured as a layer that allows electrical interconnection in the Z direction that penetrates the thickness, but has electrical insulation in the horizontal XY direction. Therefore, the conductive adhesive layer may be referred to as a Z-axis conductive layer. A detailed description thereof will be omitted below.

[0208] This embodiment may be identical to the first embodiment described above and the matters described above with reference to Figure 17, except for the location of the challenge ball (400). Therefore, redundant descriptions are omitted.

[0209]

[0210] FIG. 19 is a cross-sectional schematic diagram showing a transfer process of a third light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0211] Referring to FIG. 19, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a third light emitting element (330)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (330) is transferred onto the shock absorbing layer (150).

[0212] Through this process, the third light-emitting element (330) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner. This non-contact transfer method may be a transfer method that is performed while maintaining a distance between the third light-emitting element (330) and the electrode pad (120).

[0213] The process of transferring the third light-emitting element (330) onto the shock-absorbing layer (150) may include a step of irradiating the third light-emitting element (330) with a laser from the base substrate (200) side.

[0214] When a laser is irradiated to the third light-emitting element (330) from the base substrate (200) side, the interface between the base substrate (200) and the third light-emitting element (330) can be separated.

[0215] At this time, the third light-emitting element (330) may be a blue light-emitting element (330) that emits blue light. Hereinafter, the third light-emitting element (330) will be described as an example of a blue light-emitting element.

[0216] At this time, a protective cap (300) for protecting the blue light-emitting element (330) may be positioned on the outer surface of the blue light-emitting element (330). This protective cap (300) may be coated on the outer surface of the blue light-emitting element (330) to prevent the blue light-emitting element (330) from being damaged during the transfer process.

[0217] In the present embodiment, a conductive ball (400) for electrically connecting a blue light-emitting element (330) to the electrode pad (120) may be positioned on the electrode pad (120). That is, unlike the first embodiment in which the conductive ball (400) is attached to the blue light-emitting element (330) together with the protective cap (300), in the second embodiment, the conductive ball (400) may be positioned while being fixed on the electrode pad (120).

[0218] These conductive balls (400) can be fixed on the electrode pads (120) by an adhesive layer (140), and can also be fixed on the electrode pads (120) by a separate layer such as paste or photoresist. In addition, a conductive adhesive layer may be used instead of the conductive balls (400). For example, the conductive adhesive layer may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, etc. The conductive adhesive layer may be configured as a layer that allows electrical interconnection in the Z direction that penetrates the thickness, but has electrical insulation in the horizontal XY direction. Therefore, the conductive adhesive layer may be referred to as a Z-axis conductive layer. A detailed description thereof will be omitted below.

[0219] This embodiment may be identical to the first embodiment described above and the matters described above with reference to FIGS. 17 and 18, except for the location of the challenge ball (400). Therefore, redundant descriptions are omitted.

[0220]

[0221] Fig. 20 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the second embodiment of the present disclosure is completed.

[0222] By the process described with reference to FIGS. 17 to 19, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) within each pixel can be transferred onto the shock-absorbing layer (150).

[0223] Referring to Fig. 20, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are shown transferred and attached to a shock-absorbing layer (150).

[0224] At this time, as described above, the challenge ball (400) can be fixed and positioned on the electrode pad (120).

[0225]

[0226] FIG. 21 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to a second embodiment of the present disclosure.

[0227] In a state where a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are transferred onto the shock-absorbing layer (150) within each pixel, a process of bonding the light-emitting elements (310, 320, 330) to the electrode pad (120) can be performed.

[0228] Referring to Fig. 21, heat can be applied while the pressing part (500) is positioned on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) to bond the light-emitting elements (310, 320, 330) to the electrode pad (120).

[0229] By this process, the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) can be electrically connected to the electrode pad (120) by the conductive ball (400) positioned on the electrode pad (120).

[0230] This process may be identical to that described in the first embodiment described above, except for the location of the challenge ball (400). Furthermore, the state in which the light-emitting element manufactured through this process is assembled may be identical to that described with reference to Fig. 16. Therefore, any redundant description will be omitted.

[0231]

[0232] Fig. 22 is a cross-sectional schematic diagram showing a transfer process of a first light-emitting element in a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0233] Referring to FIG. 22, according to the third embodiment, a process is illustrated in which an assembly of a wiring board (100) having a shock absorbing layer (150) formed on a substrate (110) having electrode pads (120) formed thereon is prepared, a light emitting element (for example, a first light emitting element (310)) arranged on a base substrate (200) is positioned at the position of the electrode pads (120) on the assembly, and then the light emitting element (310) is transferred onto the shock absorbing layer (150).

[0234] At this time, the shock absorbing layer (150) in the assembly of the wiring board (100) may be positioned apart from the electrode pad (120). In this way, if the shock absorbing layer (150) is positioned apart from the board (110), the possibility of bubbles occurring can be eliminated when the shock absorbing layer (150) is directly attached to the adhesive layer (140) or the board (110).

[0235] In some cases, these bubbles may potentially change the position of the light-emitting element (310) transferred to that location. However, by positioning the shock-absorbing layer (150) away from the substrate (110) or the adhesive layer (140), situations that may arise due to the generation of these bubbles can be preemptively eliminated.

[0236] This shock absorbing layer (150) may be positioned apart from the substrate (110) or the adhesive layer (140) by a partition wall (160) positioned at the periphery of the pixel. For example, as illustrated in FIG. 12, the partition wall (160) may be positioned between individual pixels, so that the shock absorbing layer (150) may be supported by the partition walls (160) positioned on both sides of the pixel. Although FIG. 22 illustrates a one-sided arrangement, the partition walls (160) may also be positioned to partition the four sides of the unit pixel.

[0237] By this process, the first light-emitting element (310) arranged on the base substrate (200) can be transferred onto the wiring substrate (100) in a non-contact manner.

[0238] At this time, when a laser is irradiated to the first light-emitting element (310) from the base substrate (200) side, the interface between the base substrate (200) or the sacrificial layer (210) and the first light-emitting element (310) can be separated.

[0239] Electrode pads (120) arranged on a wiring board (100) can be connected to signal electrodes (or data electrodes; not shown). These electrode pads (120) or signal electrodes can be connected to a TFT layer (130) equipped with a thin film transistor (TFT).

[0240] In the present embodiment, a conductive ball (400) may be positioned on the electrode pad (120) to electrically connect the red light-emitting element (310) to the electrode pad (120). That is, in the third embodiment, the conductive ball (400) may be fixedly positioned on the electrode pad (120). However, as in the first embodiment, a similar embodiment may be configured by attaching the conductive ball (400) to the red light-emitting element (310). This embodiment may be referred to as the fourth embodiment, but any redundant description will be omitted.

[0241] These conductive balls (400) can be fixed on the electrode pads (120) by an adhesive layer (140), and can also be fixed on the electrode pads (120) by a separate layer such as paste or photoresist. In addition, a conductive adhesive layer may be used instead of the conductive balls (400). For example, the conductive adhesive layer may be an anisotropic conductive film (ACF), an anisotropic conductive paste, a solution containing conductive particles, etc. The conductive adhesive layer may be configured as a layer that allows electrical interconnection in the Z direction that penetrates the thickness, but has electrical insulation in the horizontal XY direction. Therefore, the conductive adhesive layer may be referred to as a Z-axis conductive layer. A detailed description thereof will be omitted below.

[0242] This embodiment may be identical to the second embodiment described above, except for the configuration of the shock absorbing layer (150) positioned apart from the substrate (110) or adhesive layer (140). Therefore, redundant descriptions are omitted.

[0243]

[0244] Fig. 23 is a cross-sectional schematic diagram showing a state in which the transfer of the manufacturing method of the display device according to the third embodiment of the present disclosure is completed.

[0245] By the process described with reference to Fig. 22, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) can be transferred onto the shock-absorbing layer (150) within each pixel. Here, the description of the process of transferring the green light-emitting element (320) and the blue light-emitting element (330) is omitted, but the same transfer process as that of the red light-emitting element (310) can be performed.

[0246] Referring to Figure 23, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are shown transferred and attached to a shock-absorbing layer (150).

[0247] At this time, as described above, the challenge ball (400) may be fixed and positioned on the electrode pad (120). In addition, the shock absorbing layer (150) may be positioned apart from the substrate (110) or the adhesive layer (140) by a partition wall (160) located at the periphery of the pixel.

[0248]

[0249] Fig. 24 is a cross-sectional schematic diagram showing the state in which the adhesive layer is positioned in the manufacturing method of the display device according to the third embodiment of the present disclosure.

[0250] In each pixel, a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are transferred onto the shock-absorbing layer (150), and as illustrated in FIG. 24, an adhesive layer (141) can be positioned on the transferred light-emitting elements (310, 320, 330). That is, the adhesive layer (141) can be positioned in each pixel area. This adhesive layer (141) can have substantially the same size or area as the shock-absorbing layer (150) located in each pixel area. However, it should be understood that in some cases, the adhesive layer (141) may have a different area from the shock-absorbing layer (150) located in each pixel area.

[0251] This adhesive layer (141) can be bonded to a shock absorbing layer (150) through a subsequent bonding process to form one layer.

[0252]

[0253] Fig. 25 is a cross-sectional schematic diagram showing a process of bonding a light-emitting element in a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0254] In a state where a red light-emitting element (310), a green light-emitting element (320), and a blue light-emitting element (330) are transferred onto the shock-absorbing layer (150) within each pixel, a process of bonding the light-emitting elements (310, 320, 330) to the electrode pad (120) can be performed.

[0255] Referring to FIG. 25, the adhesive layer (141) can be pressed toward the light-emitting elements (310, 320, 330) to bond the light-emitting elements (310, 320, 330) to the electrode pad (120).

[0256] For example, heat may be applied while the compression member (500) is positioned on the adhesive layer (141) to apply pressure to the adhesive layer (141) and the light-emitting elements (310, 320, 330) together with the shock-absorbing layer (150) toward the light-emitting elements (310, 320, 330), thereby bonding the light-emitting elements (310, 320, 330) to the electrode pad (120).

[0257] By this process, the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) can be electrically connected to the electrode pad (120) by the conductive ball (400) positioned on the electrode pad (120).

[0258] As described above, the shock-absorbing layer (150) and the adhesive layer (141) may have the same directional characteristics with respect to heat. For example, the shock-absorbing layer (150) and the adhesive layer (141) may have the same thermal characteristics, and when heat is applied, a reaction in the same direction may occur. For example, when heat is applied, both the shock-absorbing layer (150) and the adhesive layer (141) may be partially or completely liquefied and then hardened. In addition, the shock-absorbing layer (150) and the adhesive layer (141) may be hardened into a single layer when heat is applied.

[0259] Therefore, the adhesive layer (141) and the shock absorbing layer (150) can be formed into one layer (141) through the bonding process described above.

[0260]

[0261] Fig. 26 is a cross-sectional schematic diagram showing a state in which assembly of a light-emitting element is completed by a method for manufacturing a display device according to a third embodiment of the present disclosure.

[0262] As described above, by applying heat while positioning the pressing part (500) on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) and bonding the light-emitting elements (310, 320, 330) to the electrode pad (120), a state as shown in FIG. 26 can be achieved.

[0263] Electrode pads (120) arranged on a wiring board (100) can be connected to signal electrodes (or data electrodes; not shown). These electrode pads (120) or signal electrodes can be connected to a TFT layer (130) equipped with a thin film transistor (TFT). Accordingly, each light emitting element (310, 320, 330) can be driven by switching driving by the TFT layer (130).

[0264] For example, when the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330) are vertical light-emitting elements, a scan electrode (or common electrode; not shown) may be formed on the red light-emitting element (310), the green light-emitting element (320), and the blue light-emitting element (330).

[0265] As described above, since the shock-absorbing layer (150) and the adhesive layer (141) may have the same directional characteristics with respect to heat, after this bonding process, the shock-absorbing layer (150) and the adhesive layer (141) may be cured into a single layer (141) when heat is applied. That is, the layer referenced as 141 in FIG. 26 may mean a layer that is formed by combining the adhesive layer (141) and the shock-absorbing layer (150) while they are cured. However, in some cases, a portion of the shock-absorbing layer (150) may remain.

[0266] Additionally, a partition wall (160) may be positioned between these hardened adhesive layers (141).

[0267]

[0268] FIG. 27 is a cross-sectional schematic diagram for explaining a transfer process of a light-emitting element in a method for manufacturing a display device according to one embodiment of the present disclosure.

[0269] A process is illustrated in which a light-emitting element (for example, a first light-emitting element (310)) arranged on a base substrate (200) illustrated in FIG. 27(a) is transferred onto an assembly of a wiring substrate (100) in which an adhesive layer (140) is positioned on a substrate (110) on which an electrode pad (120) illustrated in FIG. 27(b) is formed.

[0270] As described above, the first light-emitting element (310) can be separated from the base substrate (200) by a laser lift off (LLO) method and transferred to the electrode pad (120) side. At this time, a conductive ball (400) can be positioned on the lower side of the first light-emitting element (310).

[0271] As described with reference to FIG. 11, the first light-emitting element (310) may be a red light-emitting element (310) that emits red light, and this red light-emitting element (310) may be attached to and transferred to the sacrificial layer (210).

[0272] In this way, the first light-emitting element (310) attached to the sacrificial layer (210) can be separated by irradiating the laser. At this time, the semiconductor material may be decomposed and gas may be generated. That is, gas may be locally generated between the first light-emitting element (310) and the base substrate (200) by the laser lift-off process, and the first light-emitting element (310) may fall toward the electrode pad (120) with strong energy due to this gas. That is, the first light-emitting element (310) may fall at a speed greater than the speed generated by gravity.

[0273] The first light-emitting element (310) that falls with such strong energy may not be able to settle on the adhesive layer (140) and may bounce off, as shown in Fig. 27(b). In addition, the first light-emitting element (310) may be damaged in the process of hitting the adhesive layer (140) and being bounced off.

[0274] These problems can be equally applied to the second light-emitting element (320) and the third light-emitting element (330) grown on a growth substrate and undergoing a transfer process.

[0275] However, as shown in Fig. 27(c), when a shock absorbing layer (150) exists on the wiring board (100), the first light emitting element (310) separated from the base substrate (200) by the transfer process reaches the shock absorbing layer (150). At this time, the falling first light emitting element (310) can be settled on the shock absorbing layer (150) by having the shock absorbed by the shock absorbing layer (150).

[0276] In some cases, this shock absorbing layer (150) can work together with the adhesive layer (140) to absorb the impact of the falling first light emitting element (310).

[0277] Therefore, during the non-contact transfer process, the impact of the first light-emitting element (310) is absorbed so that the first light-emitting element (310) does not bounce off, and damage to the first light-emitting element (310) due to this can also be prevented.

[0278]

[0279] Since the transfer process described above can be performed in one step, the light emitting elements (310, 320, 330) positioned on the base substrate (200) can be directly transferred onto the wiring substrate (100). For example, in a state where the light emitting elements (310, 320, 330) are formed on the growth substrate, in a so-called chip on wafer (COW) state, the direct transfer process can be performed in a single step.

[0280] Accordingly, a process of electrically connecting the light-emitting element (310, 320, 330) to the wiring board (100) can be performed immediately thereafter.

[0281] Additionally, high-precision alignment of the light-emitting elements (310, 320, 330) can be achieved through this process.

[0282] In addition, the transfer process and electrical connection process of the light-emitting element (310, 320, 330) can be simplified, thereby improving yield. As a result, the manufacturing cost and production time of the display device can be significantly reduced.

[0283] This transfer process can be used in display devices with any resolution, regardless of the display's pixel pitch. The time at which the laser lift-off is performed can be controlled.

[0284] In addition, since the transcription process described above can be performed in a non-contact manner, the interaction between materials is minimized, enabling active response to improving mass production yield.

[0285] This transfer process is applicable to vertical, horizontal, and flip-chip light-emitting devices. Furthermore, as described above, red light-emitting devices can be attached to a substrate and transferred under the same conditions as green and blue light-emitting devices positioned on a growth substrate.

[0286]

[0287] The above description is merely an example of the technical idea of ​​the present disclosure, and those skilled in the art to which the present disclosure pertains may make various modifications and variations without departing from the essential characteristics of the present disclosure.

[0288] Accordingly, the embodiments disclosed in the present disclosure are intended to illustrate rather than limit the technical idea of ​​the present disclosure, and the scope of the technical idea of ​​the present disclosure is not limited by these embodiments.

[0289] The scope of protection of the present disclosure should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present disclosure.

[0290] According to the present disclosure, a display device using a semiconductor light-emitting element such as a micro LED can be provided.

Claims

1. A step of preparing an assembly in which a shock absorbing layer is formed on a wiring board in which electrode pads are formed; A step of preparing a temporary substrate on which light-emitting elements having light-emitting grades assigned according to their positions are arranged; A step of positioning the temporary substrate on the assembly so that the light emitting elements face the shock absorbing layer; A step of transferring the light-emitting element onto the shock-absorbing layer according to the light-emitting grade; and A method for manufacturing a display device using a light-emitting element, characterized in that it comprises a step of bonding the light-emitting element to the electrode pad.

2. In the first paragraph, the individual light emitting elements are assigned and stored with a chip ID and the light emitting level. A method for manufacturing a display device.

3. In the first paragraph, the luminescence grade is given by a lighting test on the growth substrate on which the luminescent elements are grown. A method for manufacturing a display device.

4. In the first paragraph, the step of preparing the temporary substrate is A step of transferring light-emitting elements grown on the growth substrate onto an expansion tape of the temporary substrate; and A step of forming a groove so that the above light emitting elements are distinguished. A method for manufacturing a display device.

5. In the fourth paragraph, a step of expanding the expansion tape to expand the gap between the light emitting elements is further included. A method for manufacturing a display device.

6. In the fourth paragraph, the step of forming the groove is: A scribing step for distinguishing the light emitting elements while at least some of the light emitting elements are attached. A method for manufacturing a display device.

7. In the first paragraph, the step of transferring the light-emitting element onto the shock-absorbing layer includes the step of irradiating the light-emitting element with a laser from the temporary substrate side. A method for manufacturing a display device.

8. In the first paragraph, an adhesive layer is positioned between the electrode pad and the shock absorbing layer. A method for manufacturing a display device.

9. In the 8th paragraph, the shock absorbing layer and the adhesive layer have characteristics in the same direction with respect to heat. A method for manufacturing a display device.

10. In the first paragraph, the shock absorbing layer includes a nano fiber layer. A method for manufacturing a display device.

11. A laser that irradiates light toward an assembly in which a shock-absorbing layer is formed on a wiring board on one side of a temporary board on which light-emitting elements are arranged; A transport unit that transports the position of the laser; a processor controlling the above transport unit; and A memory including device information including the light emitting grade of the light emitting devices and location information on the temporary substrate is included, The above processor, The laser irradiation position is controlled by moving the transfer unit according to the element information stored in the memory. Manufacturing device for display devices.

12. In paragraph 11, The above element information further includes the element ID linked to the light emitting grade and the location information of the light emitting element. Manufacturing device for display devices.

13. In paragraph 11, The above processor controls the transfer unit so that light emitting elements of the same light emitting grade are randomly distributed over the entire area of ​​the wiring board. Manufacturing device for display devices.

14. In paragraph 11, The above luminescence grade is given by lighting inspection on the growth substrate on which the above luminescent elements are grown. Manufacturing device for display devices.

15. In paragraph 11, The above light emitting elements are arranged at regular intervals on the temporary substrate. Manufacturing device for display devices.

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