Process Uniformity in Micro-LED Manufacturing

Display module with improved bonding accuracy for micro LEDs. The module has a substrate with a region around the pixel area having higher surface energy. When bonding micro LEDs to the substrate electrodes, an adhesive layer is temporarily cured to move the excess adhesive from the pixel area to the higher surface energy region. This reduces thickness variation and misalignment of the micro LEDs compared to uniform adhesive. The higher surface energy area helps hold the micro LEDs in place during curing. The thinner adhesive between the electrodes reduces voids and gaps.

Source

Selective transfer of microLEDs to avoid defective pixels in displays. The method involves selectively transferring microLEDs from a growth substrate to a display substrate, rather than growing and transferring the entire array. It involves depositing an adhesive layer on the growth substrate with some microLEDs exposed. A backplane is deposited on the adhesive layer aligned with the exposed microLEDs. The backplane with connected microLEDs is then transferred to the display substrate. This allows avoiding defective microLEDs from the growth substrate and improving display yield.

Source

Active full-color MicroLED display device with improved yield and manufacturing efficiency by integrating the MicroLED array and driver circuitry on a single silicon substrate instead of transferring pre-made MicroLEDs. The device has a silicon substrate with an epitaxial layer of LED material on one side. MicroLEDs are formed on the epitaxial layer by etching. A pixel driving circuit is prepared on the other side of the substrate. This avoids the complex and low yield microtransfer method of attaching pre-made MicroLEDs to a display backplane.

Source

Integrated LED chip with improved reliability and yield by growing micro LED epitaxial wafers in each micro LED region surrounded by passivation. This avoids etching to define micro LED areas and reduces damage. The micro LED wafers are mesa etched with bosses. Driving structures are placed next to the mesas to avoid blocking light. Electrodes connect between the mesas and driving. This simplifies chip preparation compared to mass transfer or monolithic bonding.

Source

Efficiently forming micro LED displays by transferring micro LED wafers to a large transfer substrate with gaps between wafers. The gaps are larger than the initial micro LED spacing. This allows populating the display backplane in fewer steps compared to traditional methods. The micro LEDs are transferred in stages using the gaps: initial transfer for each color, gap fill rows, gap fill columns, and cross gap fill for each color. This reduces the number of transfer steps from hundreds to less than 20.

Source

Micro LED display chip, manufacturing method, and device that avoids brightness non-uniformity and mura issues in micro LED displays. The method involves growing the micro LED epitaxial layer on a patterned substrate with protrusions and recesses. The LEDs are formed in the recesses aligned with the protrusions. This ensures consistent LED quality, brightness, and efficiency since the LEDs grow in the same crystal orientation as the recesses. The LED array made on the patterned substrate is then connected to a backboard to create the micro LED display chip.

Source

Mass transfer method for micro LED displays that improves yield and reduces displacement errors during transfer. The method involves partially etching the original substrate with the micro LED array still attached. Then a temporary substrate is bonded to the micro LED side. Final etching completes the transfer by lifting off the original substrate through the temporary substrate. This sequential etching reduces micro LED loss and displacement compared to direct etching.

Source

Micro-LED microdisplay with separate n-GaN mesas to avoid optical crosstalk and cracking issues compared to continuous n-GaN layers. The display has an array of Micro-LED chips bonded to a CMOS driving substrate using a redistribution layer. The Micro-LED chips are made by etching separate n-GaN mesas surrounded by etched p-GaN and InGaN/GaN quantum wells. This allows passivation and electrode wiring after separating the n-GaN without cracks. The redistribution layer connects the Micro-LED chips to the CMOS substrate instead of bonding the continuous n-GaN.

Source

Efficient and accurate transfer of micro LED chips onto a driving substrate for displays using a wafer-level preprocessing and packaging technique. The method involves extracting micro LED crystals from a wafer, placing them into square tubes, arranging the tubes in a pixelated array, cutting the array into sheets, and attaching the sheets to a driving substrate. This allows large numbers of tiny LEDs to be precisely transferred and assembled into displays using a wafer-level packaging process instead of pick-and-place.

Source

Micro LED display module with improved transfer precision, reduced defects, higher throughput, and better contrast. The module has a substrate with positioned recesses to match the micro LED chips. This avoids offset during transfer and improves yield. The recesses also prevent crosstalk between pixels. The module uses quantum dot materials for full color micro LEDs with better purity. It has a transparent black matrix to improve contrast. The micro LEDs are matched to the recesses with beveled edges to improve brightness. The display uses only blue micro LEDs for consistent brightness. The black matrix is applied first then transparent encapsulation avoids brightness loss.

Source

Display panel with simplified manufacturing process for microLED displays that eliminates the need for a conductive buffer layer between the microLED chips and the driving substrate. The microLEDs are transferred to a prefabricated packaging substrate instead of directly onto the driving substrate. This allows bonding the microLED-filled packaging substrate to the driving substrate without needing a separate conductive buffer layer. The packaging substrate can have features like pits filled with adhesive to hold the microLEDs.

Source

A monolithic micro LED pixel design that enables efficient manufacturing of high resolution micro LED displays. The design involves forming multiple micro LED subpixels on a sacrificial substrate, then transferring the entire array onto a handling substrate. This allows further processing of the sacrificial substrate side while protecting the LED surface. A planarizing dielectric layer is added to align the LED surface. The sacrificial substrate is removed, leaving etched sidewalls surrounding the LEDs. This allows dense packing of micro LEDs without cross-talk. The handling substrate can then be removed for final display assembly. The monolithic pixel design enables high yield manufacturing of large micro LED arrays.

Source

Micro LED transfer method to improve yield and stability of mass transferring large numbers of micro LED chips onto a display substrate. The method involves using a specialized transfer substrate with exposed pixel electrodes and grooves. The micro LEDs are transferred onto the substrate with melting solder that surrounds the electrode contact points. This prevents solder overflow and ensures stable electrical connections. The exposed electrodes and grooves also provide alignment features for precise transfer.

Source

MicroLED display device with improved yield and simplified fabrication compared to conventional microLED displays. The device uses separate monochrome microLEDs for each color instead of integrating color conversion layers. The display is prepared by sequentially bonding and etching layers. A driving substrate, bonding layer, and monochrome microLED array are provided. A separate microLED epitaxial layer with avoidance holes is bonded over the monochrome LEDs. Etching exposes the monochrome LEDs and forms the separate color microLEDs. This reduces fabrication complexity compared to integrating color conversion layers on monochrome LEDs.

Source

Reducing interference during transfer of closely packed LEDs from growth substrates to backplanes in display manufacturing. The method involves modifying the thicknesses of LEDs in different colors to prevent collisions during transfer. The LEDs are initially grown at high density on a wafer with one LED per pixel area. Then, some LEDs are isolated and transferred to the backplane while others remain on the wafer. Additional metal is added to the remaining LEDs to increase their thickness. This allows them to be transferred without interference since the thicker LEDs now have larger gaps between them. This enables using high density growth substrates for LED fabrication, reducing cost, while still enabling reliable transfer to backplanes without collisions.

Source

Manufacturing method for micro LED displays that reduces time for transferring the micro LEDs from the growth substrate to the final display substrate while preventing non-uniformity of luminous properties. The method involves segmenting the micro LED regions on the growth substrate and simultaneously transferring the segmented regions to separate display substrates. This allows efficient transfer of all the micro LEDs without waiting for simultaneous transfers from the growth substrate. The segmented arrangements on the display substrates also prevent luminance and color uniformity issues.

Source

A method to mass transfer microLEDs from their growth substrate to a display substrate with circuitry and pads for attaching the microLEDs. The method involves flipping the microLED-containing substrate, bonding the microLEDs to the display substrate using heat, then separating the flipped substrate. This allows transferring many microLEDs at once without individually picking them up. The display substrate has driving circuitry and pads for attaching the microLEDs. The separated microLED substrate is reflowed to fix the microLEDs in place. This avoids the mass transfer problem of picking up and placing many tiny microLEDs.

Source

A manufacturing method for high-efficiency microLED displays that improves transfer accuracy and bonding stability during the transfer process. The method involves transferring multiple microLED devices from epitaxial substrates onto a temporary transfer substrate. Before transfer, metal columns are formed between adjacent microLEDs on the temporary substrate. This prevents deformation of the light-emitting layers during transfer. After transfer, the microLEDs are bonded to the display substrate and covered with a pixel-defining material. The metal columns provide stability and prevent warpage during bonding. The nanowire grid layer between the material and microLEDs further improves bonding stability.

Source

Active microLED display with improved yield and efficiency by integrating the microLED and drive electronics. The method involves forming a microLED epitaxial layer on a substrate, adding electrodes on one side far from the epitaxial layer, creating driving circuitry on the electrode side, stripping the substrate, etching the epitaxial layer based on electrode positions, and adding final electrodes on the microLED units. This directly forms active microLED display units without separate microLED and drive substrates.

Source

Efficient manufacturing method for multicolor micro LED displays that avoids the challenges of transferring and interconnecting large numbers of micro LEDs. The method involves bonding the micro LED epitaxial layers directly onto the driving circuit chips during fabrication. This is done by sequentially bonding and removing the LED epitaxial wafers from the driving chip wafer to form a multilayer structure with the LED layers bonded to the circuit chips. This enables efficient fabrication of multicolor micro LED displays by eliminating the need for separate LED and driver wafers and subsequent transfer steps.

Source

High-resolution Micro LED display substrate with improved alignment and bonding precision for better yield and reliability. The substrate has a CMOS driving substrate, barrier layer, bonding metal layer, full-circle Micro LED chip, current spreading layer, GaN layer, chip substrate, insulating layer, and common cathode electrode layer. The full-circle Micro LED chip has a unique shape that allows for more precise alignment during bonding compared to conventional rectangular chips. This improves bonding accuracy, strength, and stability. The circular shape is achieved by growing the LED epitaxy on a curved substrate before transferring to the display substrate.

Source

Manufacturing method for micro LED displays that enables direct bonding of the LED dies to the backplane without the need for interposer or transfer substrates. The method involves laser ablation to remove the LED dies from their growth substrate and then bonding the ablated LEDs directly to the backplane using a single bonding structure per LED. This allows high yield, high accuracy transfer of both horizontal and vertical LED structures without needing additional carriers. The laser ablation is cooled with nitrogen below 25°C to prevent damage.

Source

Method to manufacture high-quality micro LEDs with improved reliability and brightness compared to conventional methods. The key steps are: growing the micro LED structure in a sequence of porous and non-porous layers, forming electrical contacts on the porous layers, and passivating the exposed non-porous layers. This avoids dry etching damage to the LED structure. The porous layers can be porous DBRs with alternating porous and non-porous layers to tune the refractive index. The non-porous layers provide electrical isolation.

Source

Micro LED display chip with improved luminous efficiency and preparation method. The chip has micro LED units with a reflective layer on the sidewall instead of the top surface. This avoids light crosstalk between pixels and improves extraction. The reflective layer is formed by etching from the sidewall of the stepped micro LED structure. The etching is done without a mask since the stepped shape provides positioning. This saves process steps compared to etching from the top.

Source

A method to prepare microLED displays with high brightness for medium-sized screens that avoids the limitations of existing methods. The method involves preparing the microLED matrix by depositing electrodes on the LEDs instead of transferring individual LEDs. This allows packing the LEDs closer together without large gaps between them. It also enables using a backplane with higher current carrying capacity to drive the denser LED array. The method involves forming the first electrode on the LED side of the substrate, adding a second substrate as support, removing the original substrate, and then forming the second electrode on the LED side. This leaves the LEDs exposed for wire bonding to the driver IC.

Source

Manufacturing method for micro LED displays with improved yield and precision compared to existing methods. The method involves bonding the micro LED wafers to a temporary substrate using an adhesive layer. Then, a light shielding layer is added between the micro LED dies to isolate them and prevent cross-talk. This allows the micro LED wafers to be transferred with higher accuracy and efficiency to the final display substrate by avoiding the need for precise alignment of tiny dies.

Source

Micro LED displays with improved efficiency and yield using a transfer substrate and method. The displays have subpixels with multiple micro LEDs of different shapes or sizes instead of just one. The transfer substrate has regions for transferring the different micro LED types. The transfer method sequentially transfers the larger main micro LED first, then the smaller secondary micro LED to some subpixels. This allows flexibility in subpixel design while avoiding gaps from missing transfers.

Source

Micro LED displays with improved transfer efficiency using a sequential transfer method. The display has subpixels containing differently sized micro LEDs. The transfer process involves sequentially transferring a larger primary micro LED followed by a smaller secondary micro LED to each subpixel. This allows filling subpixels with the larger LED first and then the smaller one. It prevents voids and gaps that can occur when attempting to transfer both sizes simultaneously. The smaller secondary micro LED replaces any remaining empty subpixel space after the larger primary LED.

Source

A method for manufacturing micro LED displays with improved yield and reduced cost compared to conventional methods. The method involves transferring micro LED chips directly from their growth substrate to a separate substrate with drive circuits and bonding pads. This allows mass transfer of the active LED chips without the complexity and yield issues of epitaxially growing and processing the entire display on a single substrate. The transferred micro LED chips are fixed in place and connected to the drive circuits. This allows using optimized growth substrates for each color of LED and simplifying display substrate processing.

Source

Manufacturing method and LED device for MicroLED displays with reduced crosstalk between pixels. The method involves defining pixel regions by arranging a transparent conductive layer on one side of the LED area far from the substrate. This prevents Mesa sidewall defects and improves LED performance. The pixel regions have adjustable doping concentration in the second semiconductor layer to reduce resistance. Ion implantation or laser annealing can increase doping in the pixel area. The transparent conductive layer enables vertical current flow. This avoids lateral current leakage between pixels, reducing crosstalk.

Source

Nano-imprint manufacturing method for Micro-LED displays that eliminates the need for mass transfer processes like pick-and-place, which are complicated and expensive. The method involves using nano-imprint lithography to precisely pattern the layers of a Micro-LED display directly on the substrate, rather than transferring pre-made LEDs. This includes fabricating the buffer layer, LED structure, insulating layer, N-pole control circuit, P-pole control circuit, and connecting electrodes using nano-imprint lithography steps. This allows creating a functional Micro-LED display without the mass transfer steps, simplifying the manufacturing process and reducing costs.

Source

A method to improve the alignment precision and yield of micro LED displays by reducing the number of transfer steps. The method involves preparing the micro LED on a temporary substrate instead of the final display substrate. Then the temporary and display substrates are aligned and the micro LED is transferred in one step. This avoids separate transfers from sapphire growth substrate and temporary carrier, reducing misalignment risks.

Source

Micro LED display screen with improved manufacturing process for high resolution, high brightness and power efficiency. The display has multiple substrates stacked with exposed micro LED chips in a one-to-one correspondence between adjacent substrates. The middle substrate covers the first substrate and has through holes for exposing the micro LEDs from the first substrate. The third substrate covers the middle substrate and has separate through holes for exposing the micro LEDs from the middle substrate and the first substrate. This allows stacking multiple substrates with exposed micro LEDs for higher resolution and brightness compared to a single substrate.

Source

Low-cost processing technique for manufacturing Micro-LED flexible touch displays that reduces the production cost compared to conventional methods. The technique involves transferring multiple Micro-LED wafers to the target substrate using an elastic film with magnetic powder and an electromagnet. This allows batch transfer of many Micro-LED wafers at once, instead of individually transferring each wafer. The elastic film conforms to the target substrate shape during transfer. The magnetic powder adheres to the Micro-LEDs on the temporary substrate. The electromagnet then pulls the Micro-LEDs off the temporary substrate and onto the target substrate. This simplified batch transfer method reduces production steps and costs compared to individually transferring each Micro-LED wafer.

Source

Micro LED display backplane manufacturing method that reduces the number of microLED transfers compared to existing methods, by fabricating the microLED array directly on the growth substrate instead of multiple intermediate steps. The microLED array is grown on the substrate, then transferred as a whole to the display backplane using metal bonding. This avoids the need to pick and place individual microLEDs multiple times during transfer.

Source

Micro LED display with improved uniformity and reduced visibility of transfer boundaries. The display has adjacent transfer areas with staggered micro LED arrangements. In one area, the LEDs are in a straight line, in the other area they are offset. This prevents brightness differences when viewed from the edge between areas. A transfer head picks up and places LEDs in each area in a staggered pattern. The head rotation allows overlapping the transfer area boundaries. This avoids brightness transitions between areas.

Source

Method for manufacturing micro LED displays that reduces transfer time and improves uniformity by dividing the micro LED regions on the donor substrate and transferring them differently to the recipient substrate. This involves dividing the micro LED-covered donor substrate into multiple regions, then sequentially transferring the micro LEDs from each divided region to separate recipient substrates. By transferring the micro LEDs from different regions of the donor substrate, it prevents non-uniformity issues that can arise when transferring all the micro LEDs from the same region. This allows manufacturing the display faster by parallelizing the transfer process instead of transferring all the micro LEDs in one go.

Source

Method for manufacturing a microLED display without transferring individual microLEDs. The method involves forming the microLEDs and TFTs on the same substrate. This is done by partitioning the microLED into subpixels, planarizing it, creating via holes, and then integrating the microLED and TFT. This allows manufacturing a microLED display with multiple color microLEDs and integrated TFTs all on one substrate, simplifying production compared to transferring tiny individual microLEDs.

Source

Mass production method for large-area microLED displays that enables high resolution, high brightness microLED displays with improved yield and lower cost compared to transferring individual microLEDs. The method involves fabricating a wafer-level microLED array, transferring it to a display substrate, flattening the microLEDs, forming via holes, and integrating the microLEDs with a monolithic TFT array on the substrate. This allows thousands of microLEDs to be transferred and integrated in a single step, reducing defects and costs compared to transferring each microLED individually.

Source

A method for transferring micro LED arrays from a donor substrate to a drive substrate in a way that improves yield and efficiency compared to conventional top-emitting micro LED displays. The method involves growing micro LEDs on a donor substrate, forming columnar electrodes on each micro LED. On the drive substrate, pixel electrodes are formed and photoresist grooves are created around each pixel. Conductive adhesive is injected into the grooves. The donor and drive substrates are paired and pressed so the columnar electrodes pass through the adhesive and connect to the pixel electrodes. The donor substrate is peeled off, leaving the micro LEDs transferred to the drive substrate. The adhesive bridges the height difference between the electrodes.

Source

Method for forming micro LED displays that enables mass transfer of the LED chips to a display substrate. The method involves transferring micro LED chips from their growth substrate to a display substrate with driving circuits and bonding pads. The micro LEDs are transferred in blocks or individually using techniques like laser lift-off or mechanical pressing. The bonded micro LEDs are then reflowed to secure them in place on the display substrate. This allows high-volume transfer of micro LEDs from growth substrates to display substrates without complex pick-and-place machinery.

Source

Method for manufacturing micro LED display modules with improved efficiency and space utilization. The method involves stacking connecting members on a transfer substrate with micro LEDs, transferring the micro LEDs and connected members to a display substrate using laser lifting-off, and pressing the micro LEDs to bond with the display substrate using the connecting members. This allows precise placement and electrical connection of the micro LEDs while avoiding contact with the display substrate during transfer. The display substrate is divided into regions with one for micro LEDs and another for spare replacements. This improves yield by allowing defective LEDs to be swapped without reworking the entire display. The micro LEDs are also spaced apart with curved connecting members on the display substrate to prevent short circuits. This allows dense packing of micro LEDs without overlapping contacts.

Source

A method for manufacturing micro LED display panels that improves efficiency by group transfer of micro LEDs instead of individual transfer. The method involves batch transferring micro LED groups to sub-pixel areas of the display panel. This eliminates the need for repair of defective micro LEDs since multiple LEDs are transferred at once. The groups are bonded to common electrodes in the sub-pixel areas. This allows parallel connection of the LEDs to the electrodes. The group transfer prevents missing micro LEDs in the sub-pixel area due to misalignment during single LED transfer.

Source

Method for manufacturing microLED displays with improved yield and reliability by reducing defects during transfer of the microLED chips to the display substrate. The method involves forming the microLED chips on a growth substrate, then transferring them to a carrier substrate with electrodes facing out. Thin film transistors are formed on the display substrate, and the microLEDs are transferred from the carrier to the display substrate with the electrodes spaced apart from the substrate. This prevents bonding defects between the microLEDs and transistors.

Source

Display device using micro LEDs and manufacturing method to reduce cost and defects. The display uses vertically stacked micro LEDs instead of horizontally arranged ones. The vertical LEDs are self-assembled onto a substrate with features that guide and trap them. The vertical LEDs have electrodes on one side, allowing wiring after assembly. This reduces defects compared to horizontal LEDs with electrodes on both sides. The guided assembly prevents misalignment. The vertical LEDs have stacked layers with fixed dimensions, simplifying fabrication compared to horizontally arranged layers.

Source

Efficiently manufacturing micro LED displays with high resolution and fast transfer speed by bonding micro LEDs to a drive substrate using a water-repellent layer and empty pads. The micro LEDs have a water-repellent layer on the electrode side. The drive substrate has pads with an empty area covered by water-repellent layer. During transfer, the micro LEDs are attracted to the pads by electrostatic force due to the empty water-repellent areas. The water-repellent layers prevent bonding between the micro LEDs and pads without empty areas. This enables fast and efficient transfer of large numbers of micro LEDs to the drive substrate.

Source

Method for manufacturing micro LED displays with improved yield and reduced defects. The method involves using a specialized transfer head with an adsorption member and support structure to selectively transfer micro LEDs from a growth substrate to a display substrate. This allows adjusting the pitch and density of the micro LEDs on the display to match the growth substrate, preventing misalignment and defects. The transfer head uses vacuum suction and anodic oxide films to adsorb and release the micro LEDs. Cleaning the adsorption surface between transfers helps prevent contamination. The transfer head also has a support member to equalize the adsorption force. By optimizing the transfer process and adjusting the pitch spacing, defective micro LEDs can be removed and replaced before final assembly.

Source

Manufacturing method for high resolution microLED displays with improved pixel density and reduced chip size. The method involves forming patterned light-emitting layers on two substrates, bonding them with a sacrificial layer, then removing the sacrificial layer and transferring the patterned microLED chips onto a target substrate using a transfer substrate. This flip-chip assembly approach allows efficient transfer and assembly of dense microLED arrays. The patterned bonding layer enables convenient soldering of the microLEDs to the target substrate. Removing the sacrificial layer allows peeling off part or all of the microLEDs as a transfer step instead of manual transfer. This reduces microLED size and enables higher pixel density displays.

Source

Micro LED display manufacturing method that eliminates the need for massive chip transfer steps. The method involves growing the Micro LED chips directly on the target display panel substrate, rather than on a temporary substrate like sapphire. This allows the LEDs to be formed in-place on the display panel, avoiding the complex and yield-challenged step of transferring tiny chips to the display substrate. The Micro LEDs are grown using techniques like molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD) directly on the display panel substrate. This simplifies the manufacturing process, reduces costs, and improves yield by avoiding the transfer step.

Source

A method for making micro-LED displays that allows high-yield, low-cost production of micro-LED displays with improved reliability compared to OLED displays. The method involves soldering micro-LEDs to a display backplane instead of fusion bonding or thermo-compression bonding. The display backplane has wider contact pads with smaller internal solder pads. The micro-LEDs with smaller contact pads align and release onto the solder pads, then the solder melts to bond the micro-LEDs to the wider contact pads. This allows micro-LED transfer without requiring smooth contact surfaces. The wider pads provide better mechanical attachment and thermal spreading.

Source