Die repair process in microLED display manufacturing

Abstract

This disclosure provides a device and method for repairing dies during the manufacture of micro-LED displays. The device includes a backplane. The backplane has a plurality of backplane electrodes. Each backplane electrode contains a first material. The device includes a plurality of micro-LEDs, each having a plurality of micro-LED electrodes. Each micro-LED electrode contains a second material. Each micro-LED electrode is bonded to each backplane electrode with an alloy of the first material and the second material in between. At least one backplane electrode is bonded to a micro-LED electrode via a repair material. The device includes a plurality of subpixel isolation (SI) structures formed on the backplane. The SI structures define wells for subpixels. Each well contains its respective micro-LED between adjacent SI structures. The subpixels have a color conversion material placed within the well.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to methods and apparatuses for repairing dies during the manufacture of micro-LED displays.

Background Art

[0002] Light-emitting diode (LED) panels use an array of LEDs, where individual LEDs provide pixel elements that can be controlled individually. Such LED panels can be used in computers, touch panel devices, PDAs (Personal Digital Assistants), mobile phones, television monitors, and the like.

[0003] LED panels using micron-scale LEDs (also referred to as micro-LEDs or μLEDs) based on III-V semiconductor technology have various advantages such as being superior in energy efficiency, brightness, and lifespan compared to organic LEDs (OLEDs), and being able to simplify manufacturing due to fewer material layers in the display stack. However, there are challenges in manufacturing micro-LED panels. Micro-LEDs having different emission colors (e.g., red, green, and blue pixels) need to be manufactured on different substrates in separate processes. To integrate multiple-color micro-LED devices on a single panel, a pick-and-place step is required to transfer the micro-LED devices from their original donor substrates to the target substrate. This often involves changes to the LED structure or manufacturing process, such as introducing a sacrificial layer to facilitate die peeling. Additionally, strict requirements for placement accuracy (e.g., less than 1 μm) limit either throughput, final yield, or both.

[0004] In the manufacturing of high PPI (pixels per inch) microLED displays, achieving a high illumination yield (e.g., 99.99%) is crucial for display performance. However, in the batch transfer process used in the manufacturing of some microLED displays containing millions of microLED dies, the number of dies that are successfully transferred and illuminated is often low. Conventional die repair processes involve physical die repair during the transfer process to the double interposer, requiring new adhesive interposer materials and more steps, resulting in higher costs and reduced throughput.

[0005] Therefore, it is desirable to develop a die repair process for the mass production of micro-LED displays. [Overview of the project]

[0006] In one embodiment, the disclosure generally provides a device. The device includes a backplane. The backplane has a plurality of backplane electrodes. Each backplane electrode comprises a first material. The device includes a plurality of microLEDs, each having a plurality of microLED electrodes. Each microLED electrode comprises a second material. Each microLED electrode is bonded to each backplane electrode with an alloy of the first material and the second material in between. At least one backplane electrode is bonded to the microLED electrode via a repair material. The device includes a plurality of subpixel isolation (SI) structures formed on the backplane. The SI structures define wells for subpixels. Each well contains its respective microLED between adjacent SI structures. The subpixels have a color conversion material placed within the well.

[0007] In another embodiment, the disclosure generally provides a method for repairing a die during the manufacture of a microLED display. The method includes determining a first map of the microLED display, the first map including one or more locations of defective microLEDs. The defective microLEDs are repaired at each of the one or more locations on the first map, and repairing the defective microLEDs includes trimming the defective microLEDs from the backplane of the microLEDs to expose the backplane electrodes. Repair material is placed on the backplane electrodes. Repair microLEDs are placed on the repair material.

[0008] In another embodiment, the disclosure generally provides a system. The system includes an inspection device operable to determine a first map of a micro-LED display, a second map of a micro-LED display, and a third map of a micro-LED display. The system includes a first laser configured to trim micro-LEDs on the micro-LED display based on the second map. The system includes a dispenser configured to place a repair material on the micro-LED display based on the third map. The system includes a second laser configured to perform laser lift-off on repair micro-LEDs on a substrate based on the first map.

[0009] To enable a more detailed understanding of the above-mentioned features of this disclosure, a more specific description of this disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only exemplary embodiments and should not be considered limiting in scope, as other equally valid embodiments may be recognized. [Brief explanation of the drawing]

[0010] [Figure 1A]This is a schematic cross-sectional view of the pixel architecture of a microLED display according to an embodiment. [Figure 1B] This is a schematic cross-sectional view of the pixel architecture of a microLED display according to an embodiment. [Figure 2] This is a schematic cross-sectional view of a backplane being inspected and tested by an inspection device according to an embodiment. [Figure 3A] This is an exemplary map of a backplane according to an embodiment. [Figure 3B] This is an exemplary map of a backplane according to an embodiment. [Figure 3C] This is an exemplary map of a backplane according to an embodiment. [Figure 3D] This is an exemplary map of a backplane according to an embodiment. [Figure 4] This is a schematic diagram of the laser trim-off operation of a defective die according to an embodiment. [Figure 5] This is a schematic diagram of the backplane bump repair operation according to an embodiment. [Figure 6A] This is a schematic diagram of the repair laser lift-off operation according to an embodiment. [Figure 6B] This is a schematic diagram of the separation and transfer operations according to the embodiment. [Figure 7A] This is a schematic diagram of the lamination operation to the second polymer according to the embodiment. [Figure 7B] This is a schematic diagram of the separation and transfer operations according to the embodiment. [Figure 8A] This is a schematic diagram of the repair bonding operation to the backplane according to the embodiment. [Figure 8B] This is a schematic diagram of the second polymer separation operation according to the embodiment. [Figure 9] This is a schematic cross-sectional view of a backplane being inspected and tested by an inspection device according to an embodiment. [Figure 10A] This is an exemplary map of a backplane according to an embodiment. [Figure 10B]An exemplary map of a backplane according to an embodiment. [Figure 10C] An exemplary map of a backplane according to an embodiment. [Figure 10D] An exemplary map of a backplane according to an embodiment. [Figure 11] A schematic diagram of the laser trim-off operation of a defective die according to an embodiment. [Figure 12] A schematic diagram of the backplane bump repair operation according to an embodiment. [Figure 13A] A schematic diagram of the repair laser lift-off operation according to an embodiment. [Figure 13B] A schematic diagram of the separation and transfer operations according to an embodiment. [Figure 14A] A schematic diagram of the lamination operation onto a second polymer according to an embodiment. [Figure 14B] A schematic diagram of the separation and transfer operations according to an embodiment. [Figure 15A] A schematic diagram of the repair bonding operation onto the backplane according to an embodiment. [Figure 15B] A schematic diagram of the second polymer separation operation according to an embodiment. [Figure 16] A flowchart of method 1600 for repairing a micro LED display according to an embodiment. [Figure 17A] A schematic diagram of a system according to an embodiment. [Figure 17B] A schematic diagram of a system according to an embodiment. [Figure 17C] A schematic diagram of a system according to an embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0011] For ease of understanding, whenever possible, the same reference numerals are used to denote the same elements common to the drawings. It is contemplated that the elements and features of one embodiment can be beneficially incorporated into other embodiments without further elaboration.

[0012] This disclosure relates to a method and system for repairing dies during the manufacturing of microLED displays in general. In the manufacturing of high PPI (pixels per inch) microLED displays, achieving a high illumination yield (e.g., 99.99%) is crucial for display performance. However, in the batch transfer process used in the manufacturing of some microLED displays containing millions of microLED dies, the number of dies that are successfully transferred and illuminated is often small. Conventional die repair processes involve physical die repair during the transfer process to a double interposer, requiring new adhesive interposer materials and more steps, resulting in higher costs and reduced throughput.

[0013] In aspects of this disclosure, image analysis software or artificial intelligence (AI)-based image analysis software may be used. Additional tools that are more efficient than other repair processes may be included in the repair process.

[0014] Figure 1A is a cross-sectional view of pixel 100. Pixel 100 includes at least three microLEDs arranged on a backplane 102. The microLEDs are integrated with the backplane circuit so that each microLED 104 can be addressed individually. For example, the backplane circuit may include a TFT active matrix array with thin-film transistors and storage capacitors (not shown) for each microLED 104 to drive the microLEDs, column address lines and row address lines, column drivers and row drivers. Alternatively, the microLEDs can be driven by a passive matrix within the backplane circuit. The backplane 102 can be manufactured using a conventional complementary metal-oxide-silicon (CMOS) process. The microLEDs are connected to the backplane 102 via two or more backplane electrodes 106 and two or more microLED electrodes 108. An alloy 107 of these two electrode materials is present at the interface between the two or more backplane electrodes 106 and the two or more microLED electrodes 108. Furthermore, or alternatively, the repair material 120 may be placed at the interface between two or more backplane electrodes 106 and the alloy 107 of the two electrode materials. The repair material 120 may include a conductive material, such as a metal capable of conducting electric current. The repair material 120 may include a metal configured to bond the backplane electrodes 106 to the alloy 107. For example, the repair material 120 may include silver and / or indium.

[0015] In certain embodiments, two or more backplane electrodes 106 comprise a first metal of a first material. The first material includes, but is not limited to, gold, indium, tin, silver, aluminum, platinum, or a combination thereof. In certain embodiments, two or more micro-LED electrodes 108 comprise a second metal of a second material. The second material includes, but is not limited to, gold, silver, aluminum, platinum, indium, or a combination thereof. In certain embodiments, the first and second materials are different. An alloy 107 of the first and second materials is formed from the method described herein. The alloy 107 bonds the two or more backplane electrodes 106 to the two or more micro-LED electrodes 108 and fixes the micro-LEDs to the backplane 102. In certain embodiments, the two or more backplane electrodes 106 comprise indium and the two or more micro-LED electrodes 108 comprise gold, thereby forming an indium-gold alloy 107. In other embodiments, two or more backplane electrodes 106 may contain gold, and two or more micro-LED electrodes 108 may contain indium, thereby forming a gold-indium alloy 107. In certain embodiments, the alloy 107 has a ratio of the first material to the second material (i.e., first material:second material). The ratio of the first material to the second material is about 1:3 to about 3:1. The ratio of the first material to the second material depends on the materials used to form the alloy 107. Each micro-LED 104 is configured to emit UV light in a first wavelength range. The UV light may be white light. The micro-LEDs may be LEDs.

[0016] The subpixel isolation (SI) structures 110 are positioned above the backplane 102, and in some embodiments, on the backplane 102. Adjacent SI structures define each well of at least three subpixels. Micro-LEDs 104 are positioned in each well 113 between adjacent SI structures. Each well 113 has a width of about 0.5 μm to about 40 μm, for example, about 2 μm to about 30 μm. The SI structures 110 have a width of about 0.1 μm to about 15 μm, for example, 1 μm to 10 μm. The SI structures 110 may include organic materials such as epoxy-based photoresists.

[0017] The subpixel 112 includes a first subpixel 112a having a red conversion material 114a disposed in the well 113 of the first subpixel 112a, a second subpixel 112b having a blue conversion material 114b disposed in the well 113 of the second subpixel 112b, and a third subpixel 112c having a green conversion material 114c disposed in the well 113 of the third subpixel 112c. When the micro-LED 104a of the first subpixel 112a is turned on, the red conversion material 114a converts the light emitted from the micro-LED 104a into red light. When the micro-LED 104b of the second subpixel 112b is turned on, the blue conversion material 114b converts the light emitted from the micro-LED 104b into blue light. When the micro-LED 104c of the third subpixel 112c is turned on, the green conversion material 114c converts the light emitted from the micro-LED 104c into green light. In one embodiment, pixel 100 includes a fourth subpixel 112d. As shown in Figure 1A, the fourth subpixel 112d does not contain color conversion material, i.e., it does not contain a color conversion layer. In some embodiments, the fourth subpixel 112d may be later filled with color conversion material 114 (e.g., color conversion material such as red, green, blue, or purple). In another embodiment, the fourth subpixel 112d includes sacrificial material (not shown). In yet another embodiment, at least three subpixels contain the same color conversion material. The fourth subpixel 112d may be later filled with color conversion material 114.

[0018] In some embodiments, the color conversion material 114 may include quantum dots (QDs). The quantum dots can be sized to produce wavelengths corresponding to different colors. In one embodiment, the red conversion material 114a may include quantum dots with a size of approximately 6 nm. The blue conversion material 114b may include quantum dots with a size of approximately 4 nm. The green conversion material 114c may include quantum dots with a size of approximately 2 nm. In other embodiments, the color conversion material 114 may include nanostructures, photoluminescent materials, or organic materials.

[0019] The encapsulation layer 122 is placed on the top surface of the SI structure 110 and subpixels 112, or, in some embodiments, directly on top of them. The encapsulation layer 122 prevents reaction between the color conversion material 114 and other materials in the surrounding environment. The encapsulation layer 122 has a thickness of 10 nm or less and is one of a metal layer, a metal oxide layer, or a silicon-containing layer. The encapsulation layer includes, but is not limited to, aluminum oxide, titanium oxide, silicon nitride, tantalum (Ta), hafnium (Hf), tantalum oxide, hafnium oxide, titanium (Ti), aluminum (Al), chromium (Cr), copper (Cu), tungsten (W), zirconium (Zr), or combinations thereof. The encapsulation layer 122 can be deposited using physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD). The PVD process may include pulsed laser deposition (PLD), thermal deposition, or electron beam deposition PVD (EBPVD).

[0020] In some embodiments, the pixel 100 includes a microlens 128 positioned on the encapsulation layer 122 and on each well 113 of the subpixel 112. In some embodiments, a passivation layer 126 is positioned on the microlens 128. In other embodiments, the microlens 128 may be made of a resist material, such as a photoresist material that blocks UV light. In some embodiments that can be combined with other embodiments, the pixel 100 includes a backplane electrode 106 coupled to a microLED electrode 108, as shown in Figure 1B.

[0021] Figure 2 is a schematic cross-sectional view of the backplane 102 being inspected and tested by the inspection device 200. The backplane 102 has a plurality of micro-LEDs 104 bonded to the backplane 102. Each micro-LED 104 has two electrodes 202a and 202b, which are bonded to corresponding electrodes 204a and 204b on the backplane 102, respectively. The electrodes 204 are sometimes referred to herein as solder bumps or bumps. The backplane 102 is shown in the state immediately after the micro-LEDs 104 have been bonded to the backplane 102.

[0022] During the manufacturing of the micro-LED display, after the micro-LEDs 104 are bonded to the backplane 102, the backplane 102 and micro-LEDs 104 are inspected and tested by an inspection device 200. According to one embodiment of this disclosure, the inspection device may utilize artificial intelligence (AI)-based image analysis software. As the backplane 102 and micro-LEDs 104 are inspected and tested, the image analysis software creates a record of locations, such as position 210, where the micro-LEDs 104 should be bonded to the backplane 102 but are not present. The image analysis software may incorporate AI. In one example, as the backplane 102 and micro-LEDs 104 are inspected and tested by the inspection device 200, a defective micro-LED die 104e is unable to light up (i.e., unable to emit light of the correct frequency and / or intensity). The AI-based image analysis software also creates a record of locations, such as position 212, where the micro-LEDs 104 are present but not lit up (e.g., of a defective micro-LED die 104e). Recording positions 210 and 212 may include determining the x and y coordinates on the backplane 102 that indicate those positions. The x and y coordinates can be created by referencing a reference point on the backplane 102.

[0023] Once the inspection device 200 has completed the inspection and testing of the backplane 102, the AI-based image analysis software can generate a series of maps relating to the backplane 102 in accordance with the embodiments of this disclosure.

[0024] Figures 3A to 3D show an exemplary series of maps of the backplane 102 created by the AI-based image analysis software of the inspection apparatus 200 according to embodiments of the present disclosure. Figure 3A shows an illumination / mechanical map 300 of the backplane 102. In the illumination / mechanical map 300, dots 302 indicate locations on the backplane 102 where the micro-LEDs were properly illuminated during the inspection and testing process, while dots 304 indicate locations on the backplane 102 where the micro-LEDs were not properly illuminated during the inspection and testing process (e.g., locations 210 and 212).

[0025] Figure 3B shows the laser trim map 320 of the backplane 102. In the laser trim map 320, dots 324 indicate locations on the backplane 102 where microLEDs were present but did not light up properly during the inspection and testing process (e.g., location 212). Note that there are fewer dots 324 on the laser trim map 320 than there are dots 304 on the lighting / mechanical map 300.

[0026] Figure 3C shows a bump repair map 340 of the backplane 102. In the bump repair map 340, dots 344 indicate locations on the backplane 102 (e.g., locations 210 or 212) where AI-based image analysis software has determined to repair the backplane electrodes. Dots 344 on the bump repair map 340 may indicate the same or different locations as dots 324 shown on the laser trim map 320. The bump repair map 340 may indicate more, the same, or fewer locations shown on the laser trim map 320.

[0027] Figure 3D shows a laser lift-off (LLO) repair map 360 of the backplane 102. In the LLO repair map 360, dots 364 indicate locations on the backplane 102 (e.g., locations 210 or 212) where AI-based image analysis software has determined to place the repair micro-LED die (see Figure 6A). Dots 364 on the LLO repair map 360 may indicate the same location as dot 304 on the illumination / mechanical map 300.

[0028] Figure 4 schematically shows a defective die laser trim-off operation 400 according to an embodiment of the present disclosure. In the defective die laser trim-off operation 400, the defective microLED die 104e is trimmed from the backplane 102 (for example, using a laser). The defective microLED die 104e may be trimmed from the backplane 102 based on the fact that the defective microLED die 104e is located at position 212 on the backplane 102 and that position 212 is included in the position indicated by dot 324 on the laser trim map 320.

[0029] Figure 5 schematically shows a backplane bump repair operation 500 according to an embodiment of the present disclosure. In the backplane bump repair operation 500, a repair material 120 (e.g., indium or silver ink) is applied to an electrode 204 at position 212 by a dispenser 510 (e.g., an inkjet printer). The electrode 204 can be repaired based on the fact that the electrode 204 is located at position 212 on the backplane 102 and that position 212 is included in the position indicated by dot 344 on the bump repair map 340.

[0030] Figures 6A and 6B schematically illustrate the reparative laser lift-off operation 600 and the separation and transfer operation 650 according to embodiments of the present disclosure. When operation 600 is initiated, a plurality of reparative micro-LEDs 604 are bonded to a translucent carrier 610 and to the first polymer 612 of the first interposer 614. The reparative micro-LEDs 604 may be of the same type as the micro-LEDs 104 shown in Figures 1 and 2. The translucent carrier 610 may be made of, for example, sapphire. During operation 600, the reparative micro-LEDs 604 can be irradiated with laser light 620. A mask 630 can be formed based on the LLO reparative map 360 so that only the reparative micro-LEDs 604 at the positions indicated by the LLO reparative map 360 are exposed to the laser light 620. As shown in the figure, the repair micro-LEDs 604c and 604e are exposed to laser light 620, which causes the repair micro-LEDs 604c and 604e to detach from the translucent carrier 610.

[0031] Figure 6B schematically shows a separation and transfer operation 650 according to an embodiment of the present disclosure. The translucent carrier 610 is separated from the first interposer 614 during the separation and transfer operation 650. The repair micro-LEDs 604c and 604e remain attached to the first polymer 612, while the remaining repair micro-LEDs 604 remain bonded to the translucent carrier 610.

[0032] Figures 7A and 7B schematically illustrate the lamination operation 700 to the second polymer and the separation and transfer operation 750 according to embodiments of the present disclosure. During the lamination operation 700 to the second polymer, the repair micro-LED dies (e.g., repair micro-LEDs 604c and 604e) on the first polymer 612 are bonded to the second polymer 710 of the second interposer 714.

[0033] Figure 7B schematically shows a separation and transfer operation 750 according to an embodiment of the present disclosure. The second polymer 710 is separated from the first polymer 612 during the separation and transfer operation 750. The repair micro-LEDs 604c and 604e remain bonded to the second polymer 710 of the second interposer 714.

[0034] Figures 8A and 8B schematically illustrate a backplane repair bonding operation 800 and a second polymer separation operation 850 according to embodiments of the present disclosure. During the backplane repair bonding operation 800, the repair micro-LED dies (e.g., repair micro-LEDs 604c and 604e) bonded to the second polymer 710 of the second interposer 714 are bonded (e.g., soldered) to electrodes 204 on the backplane 102. As shown, the repair micro-LED dies are bonded to electrodes 204 at locations on the backplane 102 where micro-LEDs 104 are not present (e.g., positions 210 and 212). The repair micro-LED dies may be bonded directly to electrodes 204 or to a repair material 120 (e.g., indium or silver ink) applied to electrodes 204 during the backplane bump repair operation 500.

[0035] Figure 8B schematically shows a second polymer separation operation 850 according to an embodiment of the present disclosure. The second polymer 710 is separated from the repair micro-LEDs 604c and 604e during the second polymer separation operation 850. The repair micro-LEDs 604c and 604e remain bonded to the electrodes 204 on the backplane 102. After the completion of the second polymer separation operation 850, the backplane 102 can be considered repaired. The repaired backplane 102 may then be inspected and tested again as described above with reference to Figure 2.

[0036] According to embodiments of this disclosure, a repair process similar to the process shown in Figures 2 to 8B can be used to repair vertical chips.

[0037] Figure 9 is a schematic cross-sectional view of the backplane 902 being inspected and tested by the inspection device 900. Multiple micro-LED vertical chips 904 are bonded to the backplane 902. Each micro-LED vertical chip 904 has an electrode 908 that can be bonded (e.g., soldered) to a corresponding electrode on the backplane 902. During operation of the micro-LED vertical chip 904, a second electrode at the top of each micro-LED vertical chip 904 exchanges electricity with that micro-LED vertical chip 904. The electrode 906 may also be referred to herein as a solder bump or bump. The backplane 902 is shown in the state immediately after the micro-LED vertical chips 904 have been bonded to the backplane 902.

[0038] During the manufacturing of the micro-LED display, after the micro-LED vertical chip 904 is bonded to the backplane 902, the backplane 902 and the micro-LED vertical chip 904 are inspected and tested by an inspection device 900. The inspection device 900 can supply electrical energy to the micro-LED vertical chip 904 using inductive coupling and perform non-contact illumination inspection and mapping. According to one embodiment of the present disclosure, the inspection device 900 may utilize artificial intelligence (AI)-based image analysis software. When the backplane 902 and the micro-LED vertical chip 904 are inspected and tested, the AI-based image analysis software creates a record of locations, such as location 910, where the micro-LED vertical chip 904 should be bonded to the backplane 902 but is not present. In one example, when the backplane 902 and the micro-LED vertical chip 904 are inspected and tested by the inspection device 900, a faulty micro-LED vertical chip 904e will not illuminate (i.e., will not emit light of the correct frequency and / or intensity). AI-based image analysis software also creates a record of locations where a micro-LED vertical chip 904 is present but does not light up (e.g., a faulty micro-LED vertical chip 904e), such as location 912. Creating a record of locations 910 and 912 may involve determining the x and y coordinates on the backplane 902 that indicate those locations. The x and y coordinates can be created by referencing a reference point on the backplane 902.

[0039] Once the inspection device 900 has completed the inspection and testing of the backplane 902, the AI-based image analysis software can generate a series of maps relating to the backplane 902 in accordance with the embodiments of this disclosure.

[0040] Figures 10A to 10D show an exemplary series of maps of the backplane 902 created by AI-based image analysis software of the inspection apparatus 900 according to an embodiment of the present invention. Figure 10A shows the illumination / mechanical map 1000 of the backplane 902. In the illumination / mechanical map 1000, dots 1002 indicate locations on the backplane 902 where the micro-LED vertical chips were properly illuminated during the inspection and testing process, while dots 1004 indicate locations on the backplane 902 where the micro-LED vertical chips were not properly illuminated during the inspection and testing process (e.g., locations 910 and 912).

[0041] Figure 10B shows the laser trim map 1020 of the backplane 902. In the laser trim map 1020, dots 1024 indicate locations on the backplane 902 where a micro-LED vertical chip is present but did not light up properly during the inspection and testing process (e.g., location 912). The number of dots 1024 on the laser trim map 1020 may be the same as or less than the number of dots 1004 on the lighting / mechanical map 1000.

[0042] Figure 10C shows a bump repair map 1040 of the backplane 902. In the bump repair map 1040, dots 1044 indicate locations on the backplane 902 (e.g., locations 910 or 912) where AI-based image analysis software has determined to repair the backplane electrodes. Dots 1044 on the bump repair map 1040 may indicate the same or different locations as dots 1024 shown on the laser trim map 1020. The bump repair map 1040 may indicate more, the same, or fewer locations shown on the laser trim map 1020.

[0043] Figure 10D shows a laser lift-off (LLO) repair map 1060 of the backplane 902. In the LLO repair map 1060, dots 1064 indicate locations on the backplane 902 (e.g., locations 910 or 912) where AI-based image analysis software has determined to place the repair micro-LED vertical chip. Dots 1064 on the LLO repair map 1060 may indicate the same location as dot 1004 on the illumination / mechanical map 1000.

[0044] Figure 11 schematically shows a defective vertical chip laser trim-off operation 1100 according to an embodiment of the present disclosure. The defective micro-LED vertical chip 904e is trimmed from the backplane 902 (e.g., using a laser). The defective micro-LED vertical chip 904e may be trimmed from the backplane 902 based on the fact that the defective micro-LED vertical chip 904e is located at position 912 on the backplane 902 and that position 912 is included in the position indicated by dot 1024 on the laser trim map 1020.

[0045] Figure 12 schematically shows a backplane bump repair operation 1200 according to an embodiment of the present disclosure. In the backplane bump repair operation 1200, a repair material 120 (e.g., indium or silver ink) is applied to an electrode 906 at position 912 by an applicator 1210 (e.g., an inkjet printer). The electrode 906 can be repaired based on the fact that the electrode 906 is located at position 912 on the backplane 902 and that position 912 is included in the position indicated by dot 1044 on the bump repair map 1040.

[0046] Figures 13A and 13B schematically illustrate the reparative laser lift-off operation 1300 and the separation and transfer operation 1350 according to embodiments of the present disclosure. When operation 1300 is initiated, a plurality of reparative micro-LED vertical chips 1304 are bonded to a translucent carrier 1310 and a first polymer 1312 of a first interposer 1314. The reparative micro-LED vertical chips 1304 may be of the same type as the micro-LED vertical chips 904 shown in Figures 1 and 2. The translucent carrier 1310 may be made of, for example, sapphire. During operation 1300, the reparative micro-LED vertical chips 1304 can be irradiated with laser light 1320. A mask 1330 can be formed based on an LLO reparative map 1060 so that only the reparative micro-LED vertical chips 1304 at the positions indicated by the LLO reparative map 1060 are exposed to the laser light 1320. As shown in the figure, the repair micro-LED vertical chips 1304c and 1304e are exposed to laser light 1320, which causes the repair micro-LED vertical chips 1304c and 1304e to detach from the translucent carrier 1310.

[0047] Figure 13B schematically shows a separation and transfer operation 1350 according to an embodiment of the present disclosure. The translucent carrier 1310 is separated from the first interposer 1314 during the separation and transfer operation 1350. The repair micro-LED vertical chips 1304c and 1304e remain attached to the first polymer 1312, while the remaining repair micro-LED vertical chip 1304 remains bonded to the translucent carrier 1310.

[0048] Figures 14A and 14B schematically illustrate the lamination operation 1400 to the second polymer and the separation and transfer operation 1450 according to embodiments of the present disclosure. During the lamination operation 1400 to the second polymer, the repair micro-LED vertical chips (e.g., repair micro-LED vertical chips 1304c and 1304e) on the first polymer 1312 are bonded to the second polymer 1410 of the second interposer 1414.

[0049] Figure 14B schematically shows a separation and transfer operation 1450 according to an embodiment of the present disclosure. The second polymer 1410 is separated from the first polymer 1312 during the separation and transfer operation 1450. The repair micro-LED vertical chips 1304c and 1304e remain bonded to the second polymer 1410 of the second interposer 1414.

[0050] Figures 15A and 15B schematically illustrate a backplane repair bonding operation 1500 and a second polymer separation operation 1550 according to embodiments of the present disclosure. During the backplane repair bonding operation 1500, the repair micro-LED vertical chips (e.g., repair micro-LED vertical chips 1304c and 1304e) bonded to the second polymer 1410 of the second interposer 1414 are bonded (e.g., soldered) to electrodes 906 on the backplane 902. As shown, the repair micro-LED vertical chips are bonded to electrodes 906 at locations on the backplane 902 where micro-LED vertical chips 904 are not present (e.g., locations 910 and 912). The repair micro-LED vertical chips may be bonded directly to electrodes 906 or to a repair material 120 (e.g., indium or silver ink) applied to electrodes 906 during the backplane bump repair operation 1200.

[0051] Figure 15B schematically shows a second polymer separation operation 1550 according to an embodiment of the present disclosure. The second polymer 1410 is separated from the repair micro-LED vertical chips 1304c and 1304e during the second polymer separation operation 1550. The repair micro-LED vertical chips 1304c and 1304e remain bonded to the electrodes 906 on the backplane 902. After the completion of the second polymer separation operation 1550, the backplane 902 can be considered repaired. The repaired backplane 902 may then be inspected and tested again as described above with reference to Figure 9. Once the backplane 902 has passed the inspection and testing process, a liquid-tight filler or insulating material 1556 is placed between the micro-LED vertical chip 904 and the repair micro-LED vertical chip 1304. An indium tin oxide (ITO) coating 1560 is applied on top of the insulating material 1556 to form electrical connections to the electrodes at the top of the micro-LED vertical chip 904 and the repair micro-LED vertical chip 1304.

[0052] Figure 16 is a flowchart of a method 1600 for repairing a microLED display, such as a microLED display containing pixel 100 as described herein.

[0053] Operation 1602 includes the processor determining a first map of one or more locations on a microLED display. The first map includes one or more locations of faulty microLEDs on the microLED display. Faulty microLEDs include microLEDs that do not light up when power is supplied. For example, the processor of the inspection device 200 can determine an illumination / mechanical map 300 of one or more locations (e.g., locations 210 and / or 212) on the microLED display that do not light up when power is supplied. In embodiments of the present disclosure, method 1600 further includes supplying power to the microLED display to determine the first map.

[0054] Operation 1604 includes repairing a faulty micro-LED at each of one or more locations on the first map, since it is to be installed at each of the one or more locations. Operation 1604 includes trimming the faulty micro-LED from the backplane to expose the backplane electrodes. Repair material is applied to the backplane electrodes. The repair micro-LED 604 is placed on the repair material. For example, the processor may be able to install a repair micro-LED 604 at each of one or more locations (e.g., locations 210 and / or 212).

[0055] Figures 17A to 17C show a system 1700 configured to perform one or more operations of method 1600. System 1700 includes a controller 1702 communicatively coupled to an inspection device 1704. The controller 1702 may include one or more processors for processing signals received from the inspection device 1704. The inspection device 1704 may include one or more cameras and / or vision sensors. According to one embodiment of the present disclosure, the controller 1702 may utilize image analysis software or artificial intelligence (AI) based image analysis software. The inspection device 1704 may transmit one or more vision images and / or data of the micro-LEDs 104 and / or backplane 102, and the image analysis software or software artificial intelligence (AI) based image analysis software creates a record of locations where the micro-LEDs 104 should be bonded to the backplane 102 but are not present. In one example, when the backplane 102 and micro-LEDs 104 are inspected by the inspection device 1704, a defective micro-LED die 104e does not light up (i.e., does not emit light of the correct frequency and / or intensity). The controller 1702 uses image analysis software to create a record of the locations where micro-LEDs 104 are present but do not light up (e.g., defective micro-LED dies 104e). Creating the record may include determining the x and y coordinates on the backplane 102 that indicate their locations. The x and y coordinates may be created by referencing a reference point on the backplane 102. According to embodiments of this disclosure, the controller 1702 may use image analysis software or artificial intelligence (AI)-based image analysis software to generate a series of maps of the backplane 102.

[0056] System 1700 includes a first laser 1706 that is communicatively coupled to a controller 1702, as shown in Figure 17A. System 1700, including the first laser 1706, can be used in operation 1604. For example, the first laser 1706 is configured to use image analysis software to trim micro-LEDs 104 on a micro-LED display based on a second map generated by the controller 1702. The first laser 1706 may include a laser suitable for separating the micro-LEDs 104 from the backplane 102 and / or backplane electrodes 106.

[0057] System 1700 includes a dispenser 1708 communicatively coupled to a controller 1702, as shown in Figure 17B. System 1700, including dispenser 1708B, can be used in operation 1604. For example, dispenser 1708 is configured to use image analysis software to place a repair material on a micro-LED display based on a third map generated by the controller 1702. Dispenser 1708 may include a dispenser suitable for placing repair material on a backplane 102 and / or backplane electrode 106.

[0058] System 1700 includes a second laser 1710 that is communicatively coupled to a controller 1702, as shown in Figure 17C. System 1700, including the applicator and the second laser 1710, can be used in operation 1604. For example, the second laser 1710 is configured to perform laser lift-off on a repair micro-LED on a substrate based on a first map generated by the controller 1702, using image analysis software. The second laser 1710 may include a laser suitable for performing laser lift-off on a repair micro-LED.

[0059] As used herein, “processor,” “at least one processor,” or “one or more processors” generally refers to a single processor configured to perform one or more operations, or to multiple processors configured to jointly perform one or more operations. In the case of multiple processors, the execution of one or more operations may be divided among different processors, but one processor may perform multiple operations, or multiple processors may jointly perform a single operation. Similarly, “memory,” “at least one memory,” or “one or more memories” generally refers to a single memory configured to store data and / or instructions, or to multiple memories configured to jointly store data and / or instructions.

[0060] While the above applies to embodiments of the present disclosure, other embodiments and further embodiments of the present disclosure can be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

Claims

1. A backplane having multiple backplane electrodes, wherein each backplane electrode contains a first material, A plurality of microLEDs having a plurality of microLED electrodes, each microLED electrode comprising a second material, each microLED electrode being bonded to each backplane electrode with an alloy of the first material and the second material in between, and at least one backplane electrode being bonded to the microLED electrode via a repair material, A plurality of subpixel isolation (SI) structures formed on the backplane, wherein each SI structure defines a subpixel well, each well contains a microLED between adjacent SI structures, and each subpixel has a color conversion material disposed within the well. A device equipped with the following features.

2. The device according to claim 1, wherein the repair material is conductive.

3. The device according to claim 1, wherein the repair material comprises indium, silver, or a combination thereof.

4. The device according to claim 1, wherein the first material includes gold, indium, tin, silver, aluminum, platinum, or a combination thereof.

5. The device according to claim 1, wherein the second material includes gold, silver, aluminum, platinum, indium, or a combination thereof.

6. A method for repairing a microLED display, The first map of the microLED display is determined such that the first map includes one or more locations of defective microLEDs. The repair of the faulty micro-LED at each of the one or more locations on the first map is performed. The defective micro-LED is trimmed from the backplane of the micro-LED to expose the backplane electrodes. Placing repair material on the backplane electrode, and Placing a repair micro-LED on the repair material, Including repair, Methods that include...

7. Determining a second map of the microLED display, wherein the second map includes one or more positions of microLEDs on the microLED display. To remove the micro-LEDs located at one or more of the aforementioned positions, The method according to claim 6, further comprising:

8. Determining a third map of the microLED display, wherein the third map includes one or more positions of electrodes on the microLED display. Repairing the electrodes located at the aforementioned one or more positions, The method according to claim 7, further comprising:

9. The method according to claim 6, wherein trimming the defective micro-LEDs includes trimming the defective micro-LEDs using a first laser.

10. Masking the repair micro-LEDs on the substrate according to the first map, A second laser is used to identify the unmasked repair micro-LEDs on the substrate, The method according to claim 9, further comprising:

11. The method according to claim 6, wherein the repair material is conductive.

12. The method according to claim 11, wherein the repair material comprises indium, silver, or a combination thereof.

13. The method according to claim 6, further comprising determining the first map by supplying power to the microLED display to determine the first map.

14. An inspection device, To determine the first map of the microLED display, Determining the second map of the microLED display, To determine the third map of the aforementioned microLED display and An inspection device capable of performing the following: A first laser configured to trim the microLEDs on the microLED display based on the second map, A dispensing device configured to place a repair material on the micro-LED display based on the third map, A second laser configured to perform laser lift-off on a repair micro-LED on a substrate based on the first map, A system that includes these features.

15. The system according to claim 14, wherein the first map includes one or more locations of defective microLEDs.

16. The system according to claim 14, wherein the second map includes one or more positions of microLEDs on the microLED display.

17. The system according to claim 14, wherein the third map includes one or more locations of electrodes on the microLED display.

18. The system according to claim 14, wherein the repair material is conductive.

19. The system according to claim 18, wherein the repair material comprises indium, silver, or a combination thereof.

20. The system according to claim 14, wherein determining the first map includes supplying power to the micro-LED display to determine the first map.

Images