CN108682312B - Manufacturing method of LED array device - Google Patents

Abstract

A manufacturing method of an LED array device, using a vertical structure LED device and a motherboard, the LED device is provided with a first magnetic part made of a soft magnetic metal; the motherboard is provided with a second magnetic part made of a hard magnetic material, and: A non-magnetic insulating base layer is set on the first board body; a driving circuit layer including a plurality of pads is set on the base layer, and the pads correspond to the second magnetic part; the LED devices are scattered on the driving circuit layer, which The first magnetic part is subjected to the force of the magnetic field of the second magnetic part on the pad, so that the LED device is positioned and adsorbed on the pad; the LED device and the pad are bonded to each other; the base layer and the motherboard are separated from each other to obtain LED array device. This method enables the transfer and bonding of large quantities of LED devices to the driver circuit layers more quickly and efficiently.

Description

A kind of manufacturing method of LED array device

technical field

The invention relates to a manufacturing method of an LED array device, belonging to the technical field of LED display, especially micro-LED display.

Background technique

Micro-LED displays such as micro-LEDs or mini-LEDs are generally displays constructed by transferring and bonding huge numbers of tiny light-emitting diodes (LEDs) onto a driver circuit substrate. Micro LED displays have the advantages of good display performance (active light emission, high brightness, high contrast, high color gamut, wide viewing angle, fast response), energy saving, long working life, etc., and are considered to be more advanced displays than liquid crystal displays and organic light emitting displays. type. In the prior art, a large number of tiny LED devices are transferred and bonded to the base layer of the driving circuit to form an LED array device as the main body of the micro-LED display. Generally, a transfer head is used to transfer the LED devices one by one (or multiple batches). However, the transfer speed is slow and the efficiency is low, and it is difficult to realize the mass production of micro-LED displays.

Therefore, in the manufacture of micro-LED displays, how to transfer and bond a large number of tiny LED devices to the base layer of the driving circuit to form an LED array device more efficiently is one of the challenges faced by the micro-LED display manufacturing technology at present. important question.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a manufacturing method of an LED array device, which can transfer and bond a huge amount of LED devices to the driving circuit base layer more quickly and efficiently. The adopted technical scheme is as follows:

A manufacturing method of an LED array device, characterized in that:

A plurality of LED devices with vertical structures are provided, the inner side and the outer side of the LED devices are respectively provided with a first electrode and a second electrode, the first electrode is provided with a first magnetic part composed of a soft magnetic metal, and the first electrode is provided with a first magnetic part. the surface of the magnetic part is provided with a first bonding layer;

Provide a motherboard, the outer side of the motherboard is a first board body surface, the first board body surface defines a plurality of bonding positions that form an array, and the bonding positions are provided with hard magnetic materials. the second magnetic portion; and, using the following processing steps:

Step 1, setting a non-magnetic insulating base layer on the first plate body surface;

Step 2: A driver circuit layer is arranged on the base layer, the driver circuit layer includes a plurality of pads and a driver circuit connected to the pads, the pads are located on the bonding position of the motherboard, at least Its surface is set as the second bonding layer;

Step 3: Spread the LED device on the driving circuit layer, the first magnetic part of the first magnetic part is subjected to the force of the magnetic field of the second magnetic part on the pad, so that the LED device is positioned on the pad and the first magnetic part is adsorbed on the pad. A bonding layer is in close contact with the second bonding layer;

Step 4, bonding the first bonding layer and the second bonding layer, so that the pad is electrically connected to the first electrode of the LED device;

Step 5, separating the base layer and the motherboard from each other to obtain an LED array device.

Specifically, the LED device may be an inorganic LED device of various emission wavelengths of GaP, GaAs, GaN and other series. The LED device is a vertical structure LED device, that is, the P and N electrodes of the LED device (ie, the first and second electrodes) are located on opposite sides of the device, respectively. The first electrode can be a doped semiconductor layer (such as a P-type layer) exposed on one side of the LED device, or a conductor film layer (such as a P-type layer) covered on the doped semiconductor layer on the side of the LED device. Ni film or Ti film on the layer); the second electrode is generally a doped semiconductor layer (such as an N-type layer) exposed on the other side of the LED device, or it can be covered with a doped semiconductor layer on the other side of the LED device. A transparent conductive film layer on the layer (such as an ITO film covering the N-type layer). The semiconductor layer (such as P-type layer, N-type layer, quantum well layer) of vertical structure LED devices is generally grown on an epitaxial substrate (such as sapphire) by epitaxy (such as epitaxy by MOCVD), and finally by laser lift-off (generally). The laser is irradiated through the epitaxial substrate to the bottom of the semiconductor layer to decompose the bottom of the semiconductor layer) and other peeling methods are peeled off from the epitaxial substrate; thus, the first magnetic part of the LED device and the first bonding layer can be removed before the LED is peeled off. First, it is placed on the first electrode (finally, the inside of the LED device) by methods such as evaporation, magnetron sputtering, electroplating, and sputtering, and finally, the semiconductor layer and the above-mentioned metal film layer are peeled off from the epitaxial substrate to obtain A vertical structure LED device with a first magnetic part and a first bonding layer inside.

The first magnetic part is a soft magnetic metal, which can ensure that the first magnetic part has conductivity to form the connection of the first electrode, and it has no magnetic field in a normal state (the soft magnetic metal has low coercivity and high The metal with magnetic permeability, which is generally in a demagnetized state without a magnetic field), ensures that the individual LED devices will not attract each other and cause agglomeration. The first magnetic part is preferably a soft magnetic metal layer (relative magnetic permeability>100) composed of iron, nickel, manganese and other magnetic metals (such as pure iron) or their alloys (such as silicon steel). Preferably, the first magnetic part can be formed by an electroplating method to obtain a larger thickness (1-200 μm). Designing the first magnetic part to be thick can not only increase the gap between the first and second magnetic parts in step 3 In the process of peeling off the LED device from the epitaxial substrate, the first magnetic part can also be used to support the semiconductor layer to prevent it from being broken during the peeling process.

The first magnetic part is preferably formed by a patterning method. For example, a photosensitive resin can be coated on the first electrode and patterned into a plurality of block holes exposing the first electrode. The electroplating causes the electroplating layer of the soft magnetic metal to grow in the block-shaped holes of the photosensitive resin, and finally the photosensitive resin is peeled off to leave the block-shaped first magnetic part. During the peeling process of the semiconductor layer, the semiconductor layer covered by the first magnetic part can remain intact, while the semiconductor layer not covered by the first magnetic part will be broken (or broken in the subsequent process), forming a plurality of dimensional profiles formed by the first magnetic part. An LED device defined by the coverage area of a magnetic part, such as a circular LED device—preferably, the size of the LED device is 5-800 μm.

In order to ensure that in step 3, the LED device can be turned over or maintained in a correct posture in which the first and second bonding layers are in close contact with each other, in the LED device, it is preferable that the first magnetic part is located at the inner side of the LED device, thereby , If the LED device is adsorbed in the opposite posture, the distance between the first and second magnetic layers is far, and its adsorption force is weak, and it is easy to design a certain removal mechanism to remove it, leaving only the LED device with the correct posture. Specifically, it is preferable that the first magnetic part is disposed on the inner side of the LED device and the thickness does not exceed 1/2 of the overall thickness of the LED device. In the LED device, it is difficult to adjust the thicknesses of the semiconductor layer and the first electrode arbitrarily. Therefore, it is also preferable that a non-magnetic metal layer is also provided between the first magnetic part and the first electrode. Through the thickness of the non-magnetic metal layer It is easy to make the thickness of the first magnetic part not exceed 1/2 of the overall thickness of the LED device, and the non-magnetic metal layer can be non-magnetic such as gold, silver, copper, aluminum, etc. (in this specification, relative permeability < 10 materials are considered to be non-magnetic materials), which can be formed by electroplating and using the same patterning method as the first magnetic part, before the first magnetic part is arranged on the first electrode. superior.

The first bonding layer can be directly the surface layer of the first magnetic part (the second bonding layer needs to be made of a material with good welding performance with the first magnetic part), or it can be an additional layer specially used for bonding. film layer. In the case where the first bonding layer is an additional film layer, it can be formed on the first magnetic part by electroplating, sputtering, hot dipping, etc., in order not to affect the first and second magnetic layers in step 3 Preferably, the thickness of the first bonding layer does not exceed 1/2 of the first magnetic part. Preferably, the first bonding layer may be a low melting point metal layer or a soft metal layer, so that the first and second bonding layers can be bonded by heating or pressure bonding in step 4. When the first bonding layer is a low melting point metal layer, it is preferably a metal layer of indium or tin or an alloy layer with indium or tin as the main component; and when the first bonding layer is a soft metal layer When it is used, it is preferable that it is a soft metal layer such as gold and silver which is easy to be press-bonded. In addition, the first bonding layer can also preferably be nano-metal coatings such as nano-silver, nano-gold, etc., which can generally bond the first and second bonding layers by heating and pressurizing. The required temperature and pressure are relatively low, and the process applicability is good.

The mother plate is preferably a glass plate (such as ordinary glass, quartz glass, sapphire glass), a ceramic plate or a non-magnetic metal plate, and can also be a composite plate of the above-mentioned materials, which can be used in any way in the above-mentioned manufacturing process. The formed LED array device provides good support and does not affect the magnetic field of the second magnetic part. The second magnetic part is made of hard magnetic material, specifically, it can be made of AlNiCo permanent magnet alloy, FeCrCo permanent magnet alloy, permanent magnet ferrite, rare earth permanent magnet material or a composite of the above materials. It is made of hard magnetic material; preferably, the second magnetic part is made of NdFeB alloy. As a commonly used hard magnetic material with excellent performance, the second magnetic part made of NdFeB alloy has better economy. In a preferred solution of the present invention, the bonding position of the motherboard is provided with an accommodating hole, the second magnetic part is embedded in the accommodating hole, and the second magnetic part is embedded in the accommodating hole of the motherboard Inside, it can not only keep the surface of the first plate body flat, but also deepen the accommodating hole so that the second magnetic part has a larger volume to enhance its magnetic field. Preferably, the accommodating hole is formed on the first board body surface of the motherboard by laser engraving, mask etching, mask electrolysis (in the case where the motherboard is a metal plate), etc., so that the formed accommodating hole can be formed. The hole shape and location are very precise. The accommodating hole may be a blind hole or a through hole passing through the motherboard. The second magnetic part can be made into a shape corresponding to the above-mentioned accommodating hole, such as a cylindrical shape, and then embedded into the accommodating hole.

In the case that the size of the LED device is small and the number is huge, the second magnetic part is also required to be small in size and large in number. In a preferred solution of the invention, the method for forming the second magnetic part is as follows: filling the receiving holes of the mother board with powder of a hard magnetic material (such as NdFeB powder, the powder can be made into paste), The high temperature treatment is performed to sinter the hard magnetic material powder inside the receiving hole into the second magnetic portion. Specifically, after the motherboard is formed with the accommodating holes, the powder of the hard magnetic material can be press-coated or scraped across the surface of the motherboard to be squeezed into each accommodating hole, and the motherboard can be baked at a high temperature of 900-1200°C. The hard magnetic material powder is sintered into the second magnetic part by baking (which can be pressurized outside the accommodating hole at the same time), so that the second magnetic part does not need to be embedded into the accommodating hole one by one, and the manufacturing efficiency is very high. In order to enable the hard magnetic material powder to be filled into the accommodating hole more effectively, preferably the accommodating hole is a through hole, so that the penetration of the hard magnetic material powder in the accommodating hole can be detected from the other side of the motherboard (preferably Fully penetrated, squeeze out the other side). In order to make the mother plate adapt to the sintering temperature of the hard magnetic material powder, in a further preferred solution of the present invention, the mother plate is made of a non-magnetic metal or alloy with a melting point greater than 1500° C. Specifically, it can be made of titanium , Molybdenum, Tungsten, Chromium or its alloys made of metal plates, this motherboard not only has strong mechanical structure, non-magnetic, but also can withstand high temperature, suitable for the above-mentioned filling and sintering process. In addition, in order to be able to withstand the high temperature sintering of the hard magnetic material powder, the motherboard can also preferably be made of a ceramic material with high temperature resistance and good mechanical properties, such as zirconia ceramics.

Preferably, after the second magnetic part is disposed on the mother board, in order to keep the first board body surface flat, at least the first board body surface of the mother board can be polished. In order to make it easy to separate the base layer from the mother board in step 5, after the mother board is polished, it is also preferable to perform a viscosity reduction treatment on the surface of the first board, such as setting a silicone polymer on the surface of the first board. Coatings or coatings (formed by spraying or vacuum coating) composed of materials or fluoropolymers.

In order to ensure that the second magnetic part has a correct and sufficient magnetic field, after the mother board is completed or in the above process steps, the mother board can be placed in a magnetizer so that the strong magnetic field penetrates the mother board and the second magnetic part is subjected to Magnetization (if the motherboard is too large, it can be magnetized by scanning). Preferably, the magnetic field of the magnetizer vertically passes through the mother board during magnetization, so that the direction of the magnetic field of the second magnetic part is perpendicular to the surface of the first board body, which can penetrate to the top of the pad more effectively. Magnetizing the second magnetic part can correctly activate the second magnetic part after sintering and forming or after being demagnetized at high temperature (such as high-temperature coating and annealing in the production process of the driving circuit layer, and the bonding of the first and second bonding layers). heat-up bonding) residual magnetic field. Preferably, the second magnetic part is magnetized between step 2 and step 3, so that the second magnetic part can be repaired in step 2 or the last step 4 (in the case of repeated use of the motherboard) due to Demagnetization state that may occur due to excessive temperature.

In step 1, a non-magnetic insulating base layer is arranged on the first board surface of the motherboard. The base layer as the base layer of the driving circuit layer is required to not shield or weaken the magnetic field that the second magnetic part penetrates to the pad, and in the step During the separation process of the fifth, it has a good supporting effect on the driving circuit layer and the LED device thereon. Therefore, the base layer can be selected as an insulating, non-magnetic, organic film layer with greater tensile properties, specifically, it can be polyester (PET), cycloolefin polymer (COP), polyimide (PI) ) and other polymer film layers. Preferably, the base layer is a polyimide film. Among various polymer film layers, the polyimide film not only has good tensile and chemical resistance properties, but also has a higher glass transition temperature (400°C). ℃ above), so that it can not only withstand various high temperature conditions (such as high temperature coating, annealing) and chemical conditions (such as film layer etching) during the subsequent production of the driver circuit layer, but also withstand the first and second bonds in step 4. The high temperature required for the bonding of the bonding layer (within 350°C, it is assumed that the first and second bonding layers are bonded by the method of heating and fusion), and there is less in the process of separating the base layer and the mother board from each other (step 5). deformation to avoid damage to the driving circuit layer and device layer thereon. The thickness of the polyimide layer can be set in the range of 2˜200 μm, so as to facilitate the penetration of the magnetic field of the second magnetic part and maintain a good mechanical strength. The polyimide layer can be formed by coating polyamic acid solution on the first board surface of the mother board and subjected to high temperature or catalytic polymerization, or the formed polyimide film can be adhered to The first board is on the body.

In the drive circuit layer set in step 2, preferably the pitch of the pads is 1.2 to 5.0 times the size of the LED device. The driving circuit layer may be a passive driving layer or an active driving layer including active devices. In the case that the driving circuit layer is a passive driving layer, it can be designed so that each pad is drawn out through a lead, or it can be designed as a cross matrix—the driving circuit layer can only be designed as the row electrodes (pads) that constitute the cross matrix. are arranged on the row electrodes), while the column electrodes forming the cross matrix are arranged after the LED devices are bonded. The above-mentioned driving circuit layer can be formed by patterning methods such as photolithography and other conductive layers deposited (eg, magnetron sputtering, vapor deposition) on the base layer, especially metal layers (eg, Cu, Mo-Al-Mo). In the case where the driving circuit layer is an active driving layer, the driving circuit layer may include a TFT device (thin film transistor) for controlling the light emission of each LED device individually. Si), oxide semiconductor or organic semiconductor. In order to allow the LED device to operate with sufficient driving current, the TFT device is preferably made of low temperature polysilicon (LTPS) or indium gallium zinc oxide (IGZO) with high electron mobility. )constitute. The design of the above-mentioned active drive layer and LED device drive circuit can refer to the drive design of the existing AM-OLED display device, such as using 2T1C (that is, including two TFT devices and a capacitor, generally used in AMOLED drive circuits) or More complex pixel drive design (such as adding a compensation circuit), the only difference is that the pixel output terminal is changed to the pad, which can also be made of the above-mentioned metal film layer (such as Cu, Mo-Al-Mo ) is formed by patterning methods such as photolithography.

The surface of the pad can be directly used as the second bonding layer (generally, the first bonding layer is required to be a special and corresponding bonding layer), or another film layer can be provided on the surface of the pad as the second bonding layer. Floor. In step 4, in order to facilitate the welding of the first and second bonding layers to each other through heating treatment when the first bonding layer is a low melting point metal layer, the second bonding layer may be easily welded (melted). A metal layer with good wettability during welding, such as a gold, silver or copper plating layer, or the second bonding layer can also be a metal layer with a low melting point. The second bonding layer can also be a soft metal layer, such as a thicker pure gold plating layer, so that in the fourth step, by applying pressure on the outside of the LED device, the first bonding layer and the second bonding layer are mutually bond. Alternatively, the second bonding layer is a nano-metal coating such as nano-silver, nano-gold, etc., which can bond the first and second bonding layers by heating and pressing, but the temperature and pressure required for the bonding are required. are relatively low, and the process applicability is better. In the case where the second bonding layer is provided separately, the second bonding layer can be formed by using a coating film (such as evaporation, magnetron bonding, electroplating) combined with a certain patterning method (it can be patterned at the same time as the pad), or It can be formed by electroplating based on the pattern of the pad (electroplating can be achieved by introducing current through the driving circuit layer) or hot dip plating. In addition, the second bonding layer can also be printed with paste or nano-metal paint of low melting point metal particles Or printed on the pad.

Preferably, after the driving circuit layer is set in step 2, a positioning layer can be set on the driving circuit layer. The positioning layer is made of insulating material, and its thickness is preferably 0.6 to 2.0 times the height of the LED device. , the positioning layer includes a positioning hole corresponding to the bonding position, so that in step 3, the LED device is sucked by the second magnetic part by being embedded in the positioning hole. In the case where the above positioning layer is provided, when the LED device deviates without being embedded in the positioning hole, due to the LED device deviating from the top of the second magnetic part and the spatial isolation of the positioning layer, the second magnetic part and the first magnetic part are separated. The distance is far, so its magnetic attraction is weak, and the translation of the LED device is unlimited, so it is difficult to form a stable adsorption, only when the LED device is embedded in the positioning hole, the distance between the second magnetic part and the first magnetic part In the near future, the translation of the LED device is limited, so that more stable adsorption can be formed. Therefore, the above-mentioned positioning layer can make the LED device more accurately adsorb on the bonding site. The size of the positioning hole can be set to 1.1 to 1.5 times the size of the LED device. The positioning hole in this size range can play a better positioning role. If the positioning hole is set larger than this size, its positioning is not accurate, and if the positioning The pores are smaller than this size, which can cause the LED device to not be effectively adsorbed in step three.

The LED array device to be manufactured can also be colored by utilizing the exclusion effect of the positioning hole on the LED device larger than its size. Preferably, the LED device includes at least a first LED device, a second LED device and a third LED device with decreasing sizes in sequence, and the first LED device, the second LED device and the third LED device have different emission colors; the The positioning holes at least include a first positioning hole, a second positioning hole and a third positioning hole with decreasing sizes in sequence, and the sizes of the first positioning hole, the second positioning hole and the third positioning hole are respectively the first LED device and the second positioning hole. 1.1 to 1.5 times the LED device and the third LED device; and, in step 3, sequentially spreading the first LED device, the second LED device and the third LED device on the driving circuit layer, so that the first LED device , the second LED device and the third LED device are sequentially embedded in the first opening, the second opening and the third opening. Specifically, the first, second, and third LED devices may be GaN, GaP, and GaAs series LED devices that emit blue light, green light, and red light, respectively, and the adjacent ratios of the sizes of the first, second, and third LED devices may be set to 1.6~2.0 (that is, the size of the first LED device is 1.6~2.0 times that of the second LED device, and the size of the second LED device is 1.6~2.0 times that of the third LED device), in step three, in the first LED device When it is spread on the driving circuit layer, it cannot be embedded in the second and third positioning holes but can only be embedded in the first positioning hole (it needs to fill the first positioning hole). Similarly, the second and third LED devices It can only be embedded in the second and third positioning holes in sequence, so that LED devices of different colors are respectively embedded in the corresponding positioning holes and connected to the corresponding pads, so that the LED array device to be manufactured is colored. In addition to the first, second, and third LED devices, fourth, fifth, or even more LED devices with different sizes and colors can be further provided to further improve the color gamut range of the LED array device to be manufactured. Color settings can lead to overly complex processes and pixel structures.

Preferably, the positioning layer is a photosensitive resin coating, whereby the positioning holes can be conveniently formed by a yellow light process (ie, a patterning process of exposure and development). Preferably, the positioning layer can also be an organic silicon coating, a polyimide coating or a high temperature resistant ink layer, so that it can withstand the high temperature of the bonding of the first and second bonding layers (assuming the first and second bonding layers) The bonding layer is bonded by heating method), and the positioning hole can be formed by laser engraving process, mask etching process or micro-nano imprinting process. The position and shape of the positioning hole thus formed are accurate, which can ensure the embedding of the LED device. Effect. In order to enable the LED device to be more effectively embedded in the positioning hole in step 3, preferably the positioning hole is circular, the LED device has a circular outline, and the LED device is set to have a circular shape , which can be inserted into the positioning holes at different angles, because the efficiency of embedding the positioning holes is improved.

In step 3, the method of spreading the LED device on the driving circuit layer can be divided into a dry dispersion method and a wet dispersion method. The dry dispersion method includes smearing or spreading the dry powder composed of a large amount of LED devices on the driving circuit layer, so that the LED devices are close to the pads and are adsorbed by the second magnetic part behind the pads, and then remove the non-adsorbed ones. excess powder. In the wet dispersion method, the LED device is first dispersed in a liquid to form a dispersion liquid of the LED device, and then the dispersion liquid is brought into contact with the driving circuit layer, so that the LED device in the dispersion liquid is adsorbed on the pad. , the wet dispersion method is easy to maintain the dispersion of the LED device through the flow of the dispersion liquid, and it is easy to control the concentration of the LED device in the dispersion liquid, which is beneficial to the control of the adsorption process of the LED device. Further preferably, when the above-mentioned positioning layer is provided, the positioning layer can also be made to have a certain degree of hydrophobicity, for example, the dispersion liquid has a contact angle greater than 100° on the surface of the positioning layer, thereby making The dispersion liquid is repelled by the positioning layer and tends to contact the pads in the positioning holes, which is beneficial to guide the LED devices suspended in the dispersion liquid to the position of the positioning holes, making the adsorption process of the LED devices more accurate and efficient. The above-mentioned hydrophobic positioning layer can be made of high temperature resistant ink with high hydrocarbon olefin content, and the dispersion liquid uses water as a solvent.

Preferably, in step 3, there is also a certain removal mechanism to remove the poorly adsorbed or poorly positioned LED devices. 2) Apply mechanical vibration on the motherboard to shake off the poorly adsorbed or poorly positioned LED devices; 3), Apply a reverse magnetic field on the outer side of the motherboard to absorb the LED devices with poor adsorption or poor position; 4) Apply adhesive on the outer side of the motherboard to absorb the bad adsorption or poor position the LED device sticks off. The above method or a combination thereof can effectively remove LED devices with poor adsorption or poor position, while retaining LED devices with good adsorption and accurate position.

Based on the types of materials used for the first and second bonding layers, in step 4, the bonding of the first and second bonding layers can be performed by heating-up fusion welding (such as welding in a reflow oven), pressure welding (such as ultrasonic welding) Or a combination of the two can be achieved. So far, the LED array device based on the base layer has been formed on the motherboard.

Preferably, after step 4, a top conductive layer is further covered on the second electrode to form the second electrode connection of the LED device. Specifically, the top conductive layer can be a transparent conductive layer, such as a sputtering coating of indium tin oxide, zinc aluminum oxide or indium gallium zinc oxide, or a coating of a transparent conductive polymer (such as PEDOT), or nano-silver , graphene and other transparent conductive layers. The top conductive layer can also be a patterned non-transparent conductive film partially in contact with the second electrode, such as a metal thin film in contact with the edge of the second electrode.

Preferably, the LED array device further includes a filling layer, the filling layer is fabricated after step 4, the top conductive layer is arranged on the filling layer, and the setting steps are as follows: on the positioning layer (including the LED The outer side of the device) is covered with a filling layer, the filling layer penetrates and fills the gap between the LED device and the positioning layer; the filling layer is cured and patterned to form an exposed opening that exposes the second electrode of the LED device; and , the top conductive layer is arranged on the filling layer and the exposed opening to form the second electrode connection of the LED device. The filling layer is mainly used to fill up the gap between the LED device and the positioning layer, thereby providing a flatter surface for setting the top conductive layer and avoiding short circuit between the first and second electrodes. The filling layer can choose a coating material with good leveling, such as ink or photosensitive resin, which can flow into and fill the gap between the positioning layer and the LED device after being coated on the outside of the positioning layer and the LED device. And finally cured by baking or UV curing. Preferably, the filling layer is a photosensitive resin coating, which is easily patterned by a yellow light process to form the exposed opening. Further preferably, the filling layer can be a black or dark photosensitive resin coating, thus, it can also keep the surface of the LED array device (except the LED device) black or dark, which is beneficial to improve the LED array. The readability of the device as a display device in a strong light environment.

In order to colorize the fabricated LED array device, a coloring film layer may be further arranged on the top conductive layer. For example, in the case where the LED device is a blue LED device, the LED device can be defined as the first, second and third LED devices, at least the yellow fluorescent coating is arranged on the first and second LED devices, and the red and green The filter films are respectively arranged on the first and second LED devices; in addition, red and green color conversion layers, such as red and green phosphor coatings, can also be arranged on the first and second LED devices respectively. or quantum dot coating. The above-mentioned colored film layer can be set by printing, printing, yellow light and other methods.

In the fifth step, the base layer and the mother board can be separated from each other by methods such as mechanical peeling. Specifically, the fabricated LED array device can be directly torn off from the motherboard, or a certain peeling tape (such as UV adhesive tape) can be attached to the fabricated LED array device, and then it can be removed from the motherboard. The motherboard is peeled off to prevent the LED array device from being overstressed and causing the circuit layer on it to fail. Besides, liquid or gas can also be filled between the base layer and the mother board to separate the base layer and the mother board.

Compared with the prior art, the beneficial effects of the present invention are:

In the manufacturing method provided by the present invention, the magnetic attraction force of the first magnetic attraction part of the LED device by the magnetic field generated by the second magnetic attraction part disposed on the motherboard is used, so that the LED device can be automatically attracted to the solder to be bonded. On the disk, wherein the magnetic attraction between the first and second magnetic parts can not only make the LED device adsorb to the pad, but also realize the positioning and orientation of the LED device, so that in actual operation, the LED device is scattered on the mother board. On the first body surface of the board, a huge amount of LED devices can be transferred to the corresponding pads at the same time. method, its mass transfer efficiency should be significantly improved.

In the above-mentioned manufacturing method, since the LED device is transferred and bonded to the driving circuit layer based on the base layer, the base layer is finally peeled off from the motherboard, so that the motherboard can be reused, thus, in the actual manufacturing In the process, it is not necessary to repeat the production of the motherboard, which greatly reduces the difficulty and cost of the above-mentioned manufacturing process. In addition, since the base layer can be made of flexible materials, the LED array device made by the above manufacturing method can also be flexible, which conforms to the development trend of display technology.

The manufacturing method of the present invention will be described in further detail below through the accompanying drawings and embodiments.

Description of drawings

1 is a schematic plan view of the overall display of the first embodiment;

FIG. 2 is a schematic plan view of a partial pixel of the display of the first embodiment;

3 is a schematic cross-sectional view of a pixel of the display according to the first embodiment;

4 is a schematic diagram of the shape and film layer of the LED used in the first embodiment;

FIG. 5 is a manufacturing step (1) of the LED used in the first embodiment;

6 is a manufacturing step (2) of the LED used in the first embodiment;

FIG. 7 is a manufacturing step (3) of the LED used in the first embodiment;

FIG. 8 is a manufacturing step (4) of the LED used in the first embodiment;

FIG. 9 is a manufacturing step (5) of the LED used in the first embodiment;

FIG. 10 is a manufacturing step (6) of the LED used in the first embodiment;

Fig. 11 is the overall plan schematic diagram of the motherboard adopted in the first embodiment;

12 is a partial schematic diagram of the motherboard used in the first embodiment;

13 is a schematic diagram of a method for arranging the second magnetic portion of the motherboard used in the first embodiment;

14 is a schematic cross-sectional view of the motherboard used in Embodiment 1;

15 is a schematic diagram of forming a base layer in a manufacturing method of the display of the first embodiment;

16 is a schematic diagram of the display of Embodiment 1, and a schematic diagram of forming row electrodes in a manufacturing method thereof;

FIG. 17 is a schematic diagram of the display of Embodiment 1, in which a row electrode copper metal layer is formed in the manufacturing method;

18 is a schematic diagram of forming a positioning layer in the display of Embodiment 1, the manufacturing method thereof;

FIG. 19 is a schematic diagram of the display of Embodiment 1, and a pad is formed in the manufacturing method thereof;

20 is a schematic diagram of magnetizing the second magnetic portion in the display of the first embodiment, in the manufacturing method;

21 is a schematic diagram of the display of the first embodiment, in which the LED device is embedded in the positioning hole in the manufacturing method;

FIG. 22 is a schematic diagram of the display of the first embodiment, in which a magnet is used to remove defective LED devices in the manufacturing method;

23 is a schematic diagram of the display of the first embodiment, the LED array device (semi-finished product) thereof;

24 is a schematic diagram of the display of Embodiment 1, and a bottom electrode connection is formed in the manufacturing method thereof;

25 is a schematic diagram of the display of Embodiment 1, and a filling layer is formed in the manufacturing method thereof;

26 is a schematic diagram of the display of Embodiment 1, and a top electrode layer is formed in the manufacturing method thereof;

FIG. 27 is a schematic diagram of forming a phosphor coating in the display of the first embodiment;

28 is a schematic diagram of the display of the first embodiment, in the manufacturing method, the LED array device is peeled off from the mother board by using peeling tape;

FIG. 29 is a schematic diagram of the display of Embodiment 1, in which the peeling tape is removed in the manufacturing method;

30 is a schematic diagram of the display of Embodiment 1, and another schematic diagram of forming a top electrode layer in the manufacturing method thereof;

FIG. 31 is a schematic diagram of an alternative scheme of the manufacturing step (6) of the LED used in Example 1;

32 is a schematic plan view of the overall display of the second embodiment;

33 is a schematic diagram of a pixel of the display of the second embodiment;

34 is a schematic cross-sectional view of a sub-pixel of the display of the second embodiment;

FIG. 35 is a schematic diagram of the mother board used in the second embodiment, which forms an accommodating hole;

36 is a schematic diagram of the motherboard used in the second embodiment, which forms the second magnetic portion;

37 is a schematic cross-sectional view of the motherboard used in the second embodiment;

38 is a schematic diagram of the display of Embodiment 2, and a base layer is formed in the manufacturing method thereof;

FIG. 39 is a schematic diagram of the display of Embodiment 2, and a buffer layer and a driving circuit layer are formed in the manufacturing method thereof;

40 is a schematic cross-sectional view of the display of the second embodiment, the driving circuit layer thereof;

41 is a schematic plan view of the display of the second embodiment, the driving circuit layer of the sub-pixel;

FIG. 42 is a schematic circuit diagram of a drive circuit layer of a sub-pixel of the display according to Embodiment 2;

43 is a schematic diagram of the display of Embodiment 2, and a positioning layer is formed in the manufacturing method thereof;

44 is a schematic diagram of the display of Embodiment 2, and a second bonding layer is formed in the manufacturing method thereof;

45 is a schematic diagram of a cross-sectional view of a sub-pixel of the display according to Embodiment 2;

46 is a schematic diagram of magnetizing the second magnetic portion in the display of the second embodiment, in the manufacturing method;

47 is a schematic diagram of the display of the second embodiment, in which the LED device is embedded in the positioning hole in the manufacturing method;

FIG. 48 is a schematic diagram of the display of Embodiment 2, and the bottom electrode connection is formed in the manufacturing method thereof;

FIG. 49 is a schematic diagram of forming a filling layer in the display of Embodiment 2, in the manufacturing method thereof;

50 is a schematic diagram of forming a top electrode layer in a manufacturing method of the display of the second embodiment;

FIG. 51 is a schematic diagram of the display of the second embodiment, and a coloring layer is formed in the manufacturing method thereof;

FIG. 52 is a schematic diagram of the display of the second embodiment, in the manufacturing method, the display is peeled off from the mother board by using peeling tape;

53 is a schematic diagram of the display of Embodiment 2, in which the peeling tape is removed in the manufacturing method;

54 is a schematic diagram of a pixel of the display of the third embodiment;

55 is a schematic diagram of the display of the third embodiment, in which the blue LED device is embedded in the positioning hole in the manufacturing method;

56 is a schematic diagram of the display of the third embodiment, in which the red LED device is embedded in the positioning hole in the manufacturing method;

57 is a schematic diagram of the display of the third embodiment, in which the green LED device is embedded in the positioning hole in the manufacturing method;

58 is a schematic cross-sectional view of a sub-pixel of the display of the third embodiment.

Detailed ways

Example 1

Embodiment 1 provides a manufacturing method of an LED display 100. As shown in FIGS. 1 and 2, the display 100 is a passively driven monochrome LED display with a pixel area of 1.61 inches and a resolution of 40×32. The main body of the display 100 is an LED array 101 , which includes 40×32 LED devices 10 arranged in a square matrix, and the pitch of the LED devices 10 is 0.8 mm. The LED array 101 is driven by row electrodes 102 and column electrodes 103 crossing each other, and each pixel has the cross-sectional structure shown in FIG. 3 .

As shown in FIG. 4 , the LED device 10 is a vertical structure circular LED device of GaN-based blue light, its specification diameter is 0.3 mm, and its film layers are, from inside to outside, a first bonding layer 11, a soft magnetic metal layer (No. A magnetic portion 12 , a non-magnetic metal layer 13 , a first electrode 14 and a semiconductor layer 15 . The first bonding layer 11 is a tin metal layer with a thickness of 5 μm, the soft magnetic metal layer 12 is an iron-nickel alloy layer with a thickness of 40 μm, the non-magnetic metal layer 13 is a copper metal layer with a thickness of 40 μm, and the first electrode 14 is a thickness of 100 nm. The total thickness of the semiconductor layer 15 is 4 μm, which includes an N-type layer (n-GaN) 151, multiple quantum wells (MQWs) 152 and a P-type layer (p-GaN) 153 as the second electrode of the LED device.

The LED device 10 is suspended and dispersed in DI water to form a dispersion, and its manufacturing method is as follows:

(1), as shown in Figure 5, adopt MOCVD (metal organic compound chemical vapor deposition method) on sapphire substrate 16 to epitaxially grow N-type layer 151, multiple quantum well layer 152 and P-type layer 153 successively, form semiconductor layer 15, A nickel film is deposited on the P-type layer by magnetron sputtering to form the first electrode 14;

(2) As shown in FIG. 6, a photosensitive resin coating 17 with a thickness of 100 μm is coated on the first electrode 14 by a slit coating method, and a yellow light method (including pre-curing, mask exposure, development, hardening, etc.) is used. film and other process steps) are patterned to form a series of circular holes 171 with a diameter of 0.3 mm, wherein the first electrode 14 is exposed at the bottom of the circular holes 171, and the distance between the circular holes 171 is 40 μm;

(3) As shown in FIG. 7 , the first electrode 14 is used as the cathode, and the copper metal layer 13 is electroplated in the circular hole 171, and the electroplating current and time are controlled so that the thickness of the copper metal layer 13 is 40 μm; continue to use the first electrode 14 As the cathode, the iron-nickel alloy layer 12 was further electroplated in the circular hole, and the electroplating current and time were controlled so that the thickness of the iron-nickel alloy layer 12 was 40 μm; the first electrode 14 was continued to be used as the cathode, and the tin metal layer 11 was further electroplated in the circular hole. , control the electroplating current and time so that the thickness of the tin metal layer 11 is 5 μm;

(4), as shown in FIG. 8, the photosensitive resin coating 17 is soaked and rinsed with the film stripping liquid, leaving a series of bosses formed by superimposing the copper metal layer 13, the iron-nickel alloy layer 12 and the tin metal layer 11. 111 (height is about 85μ);

(5) As shown in FIG. 9 , stick the release tape 18 on the surface formed by the boss 111 . The release tape 18 includes a PET plastic film 181 and a 10 μm thick adhesive layer 182 , and the adhesive layer 182 can be irradiated Ultraviolet light reduces the viscosity. Due to the protrusion of the boss 111 , the viscosity reducing adhesive layer 182 can only be bonded to the top of the boss 111 ; KrF excimer ultraviolet laser 161 is irradiated from the bottom side of the sapphire substrate 16 , which penetrates the sapphire substrate 16 The bottom of the semiconductor layer 15 is absorbed by the bottom of the semiconductor layer 15, so that the bottom of the semiconductor layer 15 is thermally decomposed (reaction formula: 2GaN=2Ga+N ₂ ), so that the semiconductor layer 15 is separated from the sapphire substrate 16. Under the support of the boss 111, the convex The semiconductor layer 15 at the bottom of the platform 111 remains intact (most of the semiconductor layer 15 not supported by the boss 111 is broken, and a small part is bonded to the edge of the LED device, which will also be broken in the subsequent process), which is together with the boss 111. The LED device 10 is formed by peeling off the peeling tape 18 from the sapphire substrate 16, and using dilute hydrochloric acid to clean off the decomposed residual Ga metal at the bottom of the semiconductor layer 15;

(6) As shown in FIG. 10 , use ultraviolet light 183 (ultraviolet high-pressure mercury lamp) to irradiate the peeling tape 18 from the back to reduce the adhesive force of the viscosity-reducing adhesive layer 182, and rinse the LED device 10 with DI water 19 to form For the DI water dispersion 191 of the LED device 10, excess DI water is used to rinse off the powder of the semiconductor layer, and the excess DI water is filtered to obtain an LED device dispersion having a dispersion density of (500-1000)/ml. The LED device 10 can be kept suspended by the flow of DI water.

As shown in FIGS. 11 and 12 , a 304 stainless steel plate with a thickness of 2 mm and a size of 370 mm×470 mm is used as the motherboard 20 , and a plurality of unit areas 22 conforming to the size of the display are defined on the first body surface 21 of the motherboard 20 . The unit area includes a pixel area 23 that conforms to the display area of the display 100. In each pixel area 23, a plurality of bonding positions 24 corresponding to the centers of the pixels of the display 100 are defined. As shown in FIG. 13, a laser 251 is used for bonding. A circular accommodating hole 25 with a diameter of 400 μm and a depth of 0.5 mm is engraved on the site, and a micro-neodymium magnet 26 with a diameter of 400 μm and a height of 0.52 mm is embedded in each accommodating hole 25, thereby forming a series of second magnetic parts. The first plate body surface 21 is mechanically polished (mainly polishing the protruding top of the neodymium magnet), and then a layer of fluoropolymer coating 27 is sprayed on the first plate body surface 21, and the coating 27 is cured to form the plate surface shown.

As shown in FIG. 15 , the polyamic acid solution is coated on the first board body surface 21 by the slit coating method, and the polyimide film 31 with a thickness of 50 μm as the base layer is thermally baked to polymerize, as shown in FIG. 16 , As shown in FIG. 1 and FIG. 2 , a Mo-Al-Mo metal film 321 (ie, "molybdenum-niobium-aluminum-neodymium-molybdenum-niobium" 3 layer alloy film, or other metal films with good conductivity) and adopt photolithography process (including photoresist coating, photoresist pre-curing, mask exposure to photoresist, photoresist development, metal film Etching, photoresist stripping and other process steps) are patterned into 32 row electrodes 32, the row electrodes 32 have a width of 500 μm and a spacing of 300 μm, which are connected to the first pin 322 (also patterned from the bottom electrode layer). ). As shown in FIG. 17 , the motherboard 20 is immersed in a copper electroplating bath, and the row electrodes 32 are used as cathodes (the row electrodes are temporarily connected to each other to facilitate the connection during electroplating, and are finally cut off when they are die-cut into display units), and further in A copper metal layer 323 with a thickness of 5 μm is electroplated on the row electrodes.

As shown in FIG. 18 , a 100 μm-thick polyimide coating 33 is further printed on the first board body surface 21 as a positioning layer, and the positioning layer 33 is engraved with a laser, and the power and engraving speed of the laser are controlled. A plurality of positioning holes 331 with a diameter of 350 μm are formed thereon and the row electrodes 32 are exposed at the bottom thereof, thereby forming pads 324 for soldering the LED device. As shown in FIG. 19 , the motherboard 20 is immersed in an electroplating bath of metal tin, and the row electrode 32 is used as the cathode, and a tin metal layer 325 with a thickness of 30 μm is electroplated on the pad 324 as the second bonding layer.

As shown in FIG. 20 , the motherboard 20 is placed in a scanning magnetizer 261 , and the magnetic field 262 of the magnetizer 261 vertically penetrates the motherboard 20 to magnetize the second magnetic portion 26 .

As shown in Figure 21, the motherboard 20 is fixed on the vibration table (not marked on the figure), and the vibration table provides the motherboard with lateral vibration 411 (along the motherboard surface) and longitudinal vibration 412 (vertical vibration) with a frequency of 20 to 200 Hz. (main board surface), the LED device dispersion 191 is sprayed on the first board body surface, the first magnetic part 12 of the LED device 10 is subjected to the magnetic field of the second magnetic part 26, and the first bonding layer 11 is directed toward the mother board. The posture of 20 (fluid resistance and magnetic attraction work together, which will cause the LED device 10 to tend to maintain this posture) is attracted to the positioning hole 331 and embedded in the positioning hole 331 to keep the first and second bonding layers 11, 325 close to each other . The lateral vibration 411 of the vibration table can make the LED device 10 move horizontally on the first board body surface 21 and fall into the positioning hole 331, thereby improving the efficiency of the adsorption process of the LED device 10; the scouring effect and vibration when the dispersion liquid 191 is sprayed The longitudinal vibration 412 of the stage can flush and shake off poorly adsorbed and poorly positioned LED devices. As shown in FIG. 22 , after the adsorption is completed, the motherboard 20 passes through the gate 42 with the magnet 421 on the upper side, so as to further adsorb the poorly adsorbed or poorly positioned LED devices through the magnet 421 (the height of the gate 42 can be adjusted to avoid Adsorb good LED devices too). The above steps may be repeated so that the LED device 10 is sufficiently embedded in the positioning hole 331 to form the LED array shown in FIG. 23 .

Use an air knife to blow off the remaining LED device dispersion on the motherboard. As shown in Figure 24, the motherboard is passed through a 300°C reflow oven, so that the first and second bonding layers 11 and 325, which are both tin metal layers, are melted and formed. The bonding layer 43 is formed by mutual wetting. Thus, each LED device 10 is soldered on the pad 324, and the first electrode 14 thereof forms a bottom electrode connection with the row electrode 32 of the driving circuit layer.

As shown in FIG. 25 , a 20 μm-thick negative black photosensitive resin layer 44 is further coated on the first board body surface 21 as a filling layer, which penetrates into and fills the gap between the LED device 10 and the positioning hole 331 (can be evacuated Remove air bubbles in the gap), and pattern the filling layer 44 by using a yellow light process to form an opening (exposed port) 441 on the top of the LED device 10 exposing the second electrode 153 . As shown in FIG. 26 , a layer of indium tin oxide film 45 as a top electrode layer is further deposited on the motherboard by magnetron sputtering, and the indium tin oxide film 45 is patterned into 40 column electrodes 451 by a photolithography process. The column electrodes 451 are connected to the second pins 452 whose periphery is also patterned by the indium tin oxide film 45 (refer to FIGS. 1 and 2 ).

So far, the fabrication of the LED array device 101 on the motherboard 20 has been completed. As shown in FIG. 28 , a layer of peeling tape 47 is attached to the LED array device 101 , and the peeling tape 47 includes a PET plastic film 471 and a UV adhesive 472 . As shown in FIG. 29 , with the aid of the peeling tape 47 Next, the LED array device 101 is torn off from the motherboard 20, and is cut into individual display units using a knife die. As shown in FIG. 29, the flexible LED display 100 can be obtained by irradiating the ultraviolet light 473 to remove the peeling tape 47; , plastic board and other rigid boards, which can be straight or curved), and then irradiate ultraviolet light to remove the peeling tape to obtain the rigid LED display 100 fixed on the support board.

In other solutions of this embodiment, the soft magnetic metal layer 12 can also be changed to a coating of pure iron or silicon steel, and the second magnetic portion 26 can also be changed to AlNiCo permanent magnet alloy, FeCrCo permanent magnet alloy, Permanent magnet ferrite, other rare earth permanent magnet materials or composite hard magnetic materials composed of the above materials. In other solutions of the present invention, the phosphor coating 46 can be omitted to obtain a blue LED display, and the LED device 10 can also be changed to LED devices of other luminescent colors such as GaP, GaAs (the ratio of the epitaxial substrate and the semiconductor layer) Corresponding changes should be made, refer to the existing technology in the light-emitting semiconductor industry) to obtain LED displays of other colors.

In other solutions of this embodiment, one of the first and second bonding layers 11 and 325 can also be changed to a gold plating layer (such as an electroplating layer or a vacuum plating layer), and the gold plating layer and the melted tin metal layer can also be Has good wettability and is easy to form welds. The first and second bonding layers 11 and 325 can also be changed to gold plating layers, and the first and second bonding layers can be welded by means of pressure welding such as ultrasonic welding. In addition, at least one of the first and second bonding layers 11 and 325 can be changed to a nano-silver or nano-gold coating, and the first and second bonding layers 11 and 325 can be formed by heating and pressure welding. Welding occurs.

In other solutions of this embodiment, the motherboard 20 can also be changed to a glass plate, a quartz glass plate, a sapphire substrate or a ceramic plate or other non-magnetic metal plates. The accommodating hole 25 can be formed by laser engraving or mask etching (for example, when the mother board 20 is a glass plate or a quartz glass plate, ammonium bifluoride is used for mask etching).

In other solutions of this embodiment, the positioning layer 33 can also be replaced with a more flexible silicone coating or a lower cost high temperature resistant ink printing layer. Besides, the positioning layer 33 can be changed to be made of a photosensitive resin coating, and the positioning holes 331 thereof can be formed by a yellow light process to have a more precise shape.

As shown in FIG. 30 , in other solutions of this embodiment, the top electrode layer 45 can also be changed to a thin film of metal or alloy such as Mo-Al-Mo, which can be coated by magnetron sputtering and other methods and patterned as The column electrode 451 has a light exit hole 452 at the top of the LED device 10 , and the edge of the light exit hole 452 contacts the second electrode 153 on the top of the LED device 10 to form a top electrode connection. When the top electrode layer 45 is made of a metal film layer, the filling layer 44 does not need to be a black photosensitive resin layer. In order to reduce the reflected light, a black ink layer (not shown) can be further covered on the top electrode layer. The black ink layer can have holes on the top of the LED to facilitate the light transmission of the LED device. The black ink layer also The ink layer may be semi-transparent and completely cover the display surface, which is beneficial to further reduce display reflections.

In other solutions of this embodiment, the LED device 10 can also be dried into powder, and the step of spraying the LED device dispersion liquid is changed to the step of spreading the LED powder (which can be driven by airflow), which can also make The LED device 10 is transferred to the pad 324 , wherein the LED device 10 that is not firmly adsorbed can be removed by blowing with an air knife.

As shown in FIG. 31 , in other solutions of this embodiment, in the process of peeling off the LED device 10 from the sapphire substrate 16 , a magnet 18 ′ can also be used instead of the peeling tape 18 . Specifically, the magnet 18 ′ can be placed on the front side of the sapphire substrate 16 , and the bottom side of the sapphire substrate 16 is irradiated with the ultraviolet laser 161 to thermally decompose the bottom of the semiconductor layer 15 . disappearing (or weakening), the LED device 10 will be attracted to the magnet 18 ′ under the action of the magnetic force between the first magnetic part 12 and the magnet 18 ′ to realize peeling. DI water or other fluids can be used to rinse the LED device 10 from the magnet 18 ′ directly, or other mechanical methods can be used to scrape the LED device 10 from the magnet; the magnet 18 ′ can also be an electromagnet, which can be passed through The LED device is separated from the magnet by withdrawing the magnetic field; in addition, a cushion film 181' can also be attached to the magnet 18', so that the LED device 10 is adsorbed on the cushion film, and finally the magnet 18' is removed, The LED device 10 is peeled off from the pad film 181'.

Embodiment 2

As shown in FIGS. 32-34 , what is to be fabricated in the second embodiment is an active-matrix-driven color LED display 200, which has a pixel area of 26 inches and a resolution of 1920×1080. Each pixel 201 further includes a red LED display. Sub-pixels 202 of four primary colors (R), green (G), blue (B), and white (W). The main body of the display 200 is an LED array 203 , which includes a total of 8,294,400 LED devices 10 of 1920×1080×4 arranged in a square matrix, and the pitch of the LED devices 10 is 150 μm.

The LED device 10 of the second embodiment is basically the same as the first embodiment (refer to FIG. 4 ), the difference is that the diameter of the LED device of the second embodiment is 100 μm, and the thickness of the soft magnetic metal layer and the copper metal layer are both 20 μm, The first bonding layer was changed to an indium metal layer with a thickness of 3 μm. The LED device is suspended in DI water to form a dispersion with a dispersion density of (1000～2000)/ml, and the manufacturing method thereof is also the same as that in Example 1 (the first bonding layer needs to be changed to electroplating indium).

The motherboard is a titanium metal plate with a thickness of 0.5mm and a size of 640mm×400mm (it can withstand high temperatures above 1500°C. In addition, the motherboard can also be a tungsten, molybdenum alloy plate or a zirconia ceramic plate). The unit area and the pixel area corresponding to the display are defined on the first board body, and the bonding positions corresponding to the sub-pixels 202 of the display are defined in the pixel area. As shown in FIG. 35, a laser 251 is used for bonding A circular through hole 25 with a diameter of 100 μm is engraved on the position 202. As shown in FIG. 36, a paste 261 made of NdFeB powder (particle size is 1 to 5 μm) is scraped across the first board body surface 21. And apply pressure to it so that the paste 261 is squeezed through each accommodating hole 25, the motherboard 20 is placed in an oven at 110°C to remove moisture, the paste remaining on both sides of the motherboard 20 is polished and removed, and the motherboard 20 is placed at 1000 °C. The pressure sintering is performed in a pressure sintering furnace at a temperature of ℃, so that the neodymium iron boron powder in the receiving hole 25 is sintered to form the neodymium iron boron magnet 26 as the second magnetic part. The two board body surfaces of the mother board 20 are polished, and then a coating layer 27 of fluoropolymer is sprayed on the first board body surface 21, thereby forming the first board body surface as shown in FIG. 37 .

As shown in Figures 38 and 39, a polyamic acid solution was coated on the first board body surface 21 by a slit coating method, and the polyimide film 31 with a thickness of 10 μm was formed as a base layer by heat-baking polymerization. Silicon nitride (SiN _x ) and silicon oxide (SiO ₂ ) films as buffer layers 32 are sequentially deposited on the amine film 31 by PECVD method, and an LTPS array manufacturing process (such as a nine-time photolithography top gate process, or reference The prior art of flexible AM-OLED) forms the driving circuit layer 33 on the buffer layer 32 .

As shown in Figures 40-42, the main body of the driving circuit layer 33 is composed of scan lines 331 (along the X direction, each pixel corresponds to two scan lines, 2160 in total), data lines 332 (along the Y direction, each pixel corresponds to An array formed by crossing two data lines (3840 in total) and power lines 333 (side by side with the data lines) (also includes peripheral circuits, which will not be described in detail here), wherein the pitch of the scan lines 331 and the data lines 332 Both are 150 μm. Each sub-pixel 202 corresponds to an intersection of the array, and its circuit mainly includes: a first thin film transistor ( T1 ) 334 , a second thin film transistor ( T2 ) 335 and a capacitor C 336 . The gate and source of T1 are connected to the scan line 331 and the data line 332 respectively, the drain is connected to one end of the capacitor C and the gate of T2, the other end of the capacitor C and the source of T2 are connected to the power line 333, the T2 The drain is connected to the pad 339, so that T1 can be controlled by the row scan signal of the scan line 331 to write the voltage signal of the corresponding data line 332 into the capacitor C, and the gate of T2 is maintained by the capacitor C within one frame The voltage is used to control the channel current of T2, thereby further controlling the luminous brightness of the LED device corresponding to the sub-pixel 202. In the driving circuit layer 33, the pad 339 is connected to the drain of T2 through the via hole 338 on the planarization layer 337, and the pad 339 is formed by photolithography of the Mo-Al-Mo film deposited by magnetron sputtering.

As shown in FIG. 43 , a photosensitive resin coating layer 34 with a thickness of 80 μm as a positioning layer is further coated on the driving circuit layer 33 by a slit coating method, and a plurality of positioning circular holes 341 with a diameter of 110 μm are formed by a yellow light process. The holes 341 correspond to the respective pads 339 to expose the pads 339 at their bottoms.

As shown in FIG. 44 , by further electroplating, an indium metal layer 35 with a thickness of 30 μm is plated on the pad 339 as a second bonding layer. During electroplating, a positive voltage may be applied to the scan line 331 and the data line 332 of the driving circuit layer 33, and a negative voltage may be applied to the power supply line 333, thereby making the pad 339 a cathode. After the indium metal layer 35 is formed, the pixel structure of the driving circuit layer is shown in FIG. 45 .

The subsequent processing steps of the display 200 mainly include:

(1) As shown in FIG. 46, magnetize the second magnetic part 26; (2) As shown in FIG. 47, spray the LED device dispersion 191 on the first board surface 21, so that the LED device 10 Under the action of the magnetic fields of the first and second magnetic parts 12 and 26, they are embedded into the positioning holes 341 and keep the first and second bonding layers 11 and 35 in close contact with each other; (3), as shown in FIG. The two bonding layers 11 and 35 are welded; (4), as shown in FIG. 49 , a filling layer 44 is further arranged on the first board body surface 21, and the filling layer 44 is patterned to have the second electrode 153 of the LED device exposed. Opening 441; (5), as shown in FIG. 50, set the top electrode layer 45; (6), as shown in FIG. 51, set the colored layer 46 on the top electrode layer 45; (7), as shown in FIG. 52, As shown at 53, the display 200 is peeled off from the motherboard 20 using the peeling tape 47 and the ultraviolet light 471. Above-mentioned steps (1)～(4) and (7) can adopt the same processing method with embodiment one. In step (5), the top electrode layer 45 can also use the same transparent conductive film or patterned metal thin film as in the first embodiment, the difference is that it does not need to be patterned as column electrodes. In step (6), a black photosensitive resin coating layer 461 with a thickness of 10 μm is arranged on the top electrode layer 45 and a plurality of circular holes 462 (diameter) corresponding to the top of the LED device 10 are patterned by a yellow light process. 100 μm), using the inkjet printing method, fill the R, G, and W sub-pixels of each pixel with red quantum dot paint 4631, green quantum dot paint 4632 and white phosphor paint 4633 and dry, and the B sub-pixel does not need The paint is filled, thereby colorizing the display.

In other solutions of this embodiment, the driving circuit layer 33 may also adopt a further improved TFT circuit design, such as a TFT circuit with compensation design, for details, please refer to the existing pixel circuit design of AM-OLED. The LTPS-TFT device of the driving circuit layer 33 can also be changed to an IGZO-TFT device, and reference is made to the existing IGZO-TFT array substrate manufacturing process.

In other solutions of this embodiment, the red light quantum dot paint 4631 and the green light quantum dot paint 4632 can be replaced with a red light phosphor paint 4631 ′ and a green light phosphor paint 4632 ′, respectively.

Embodiment 3

As shown in FIG. 54 , the display 300 to be fabricated in the third embodiment is basically the same as that in the second embodiment, the difference is that each pixel 301 includes a red sub-pixel (R sub-pixel) 3021, a blue sub-pixel 3022 ( B subpixels) and two green subpixels 3023 (G subpixels). In order to omit the step of setting the coloring layer, the third embodiment adopts LED devices of three colors, which are respectively a red LED 101 (GaAs LED), a blue LED 102 (GaN LED) and a green LED 103 (GaPLED). The diameters of the LED devices are 100 μm, 162 μm, and 50 μm, respectively. The structure and manufacturing steps (the epitaxial substrate and process parameters used may be different) are the same as the LED devices used in Example 2, and they are made as DI water dispersions 1911 and 1912 respectively. and 1913.

The design and fabrication steps of the motherboard, the base layer and the driving circuit layer in the third embodiment are basically the same as those in the second embodiment. The difference is that in the positioning layer 34, the positioning round holes are divided into three sizes of the first positioning hole 3411, the second positioning hole 3412 and the third positioning hole 3413 with diameters of 110 μm, 180 μm and 55 μm respectively (the pads also need to be with modification), which correspond to the R sub-pixel 3021, the B sub-pixel 3022, and the G sub-pixel 3023, respectively.

The subsequent processing steps of the display 300 are basically the same as those in the second embodiment. The difference is that there is no need to set the colorization layer on the display, and the process of embedding the LED device into the positioning hole includes:

(1) As shown in FIG. 55 , the same method as in the first or second embodiment is used to spray the blue LED dispersion liquid 1912 on the first body surface 21, so that the blue LED device 102 is in the first and second The magnetic parts 12 and 26 are embedded in the second positioning hole 3412 under the action of the magnetic field and keep the first and second bonding layers 11 and 35 close to each other. Due to the size, the blue LED device 102 cannot be embedded in the first and third bonding layers 11 and 35 . in the positioning holes 3411 and 3413;

(2) As shown in FIG. 56, the red LED dispersion liquid 1911 is sprayed on the first plate body surface 21 by the same method, so that the red LED device 101 is embedded under the action of the magnetic fields of the first and second magnetic parts 12 and 26. into the first positioning hole 3411 and keep the first and second bonding layers 11 and 35 close to each other. Since the second positioning hole 3412 has been occupied, and the third positioning hole 3413 is too small, the red LED device 101 cannot be embedded in it. in the second and third positioning holes 3412 and 3413;

(3) As shown in FIG. 57 , the green LED dispersion 1913 is sprayed on the first board surface 21 by the same method, so that the green LED device 103 is embedded under the action of the magnetic fields of the first and second magnetic parts 12 and 26 into the third positioning hole 3413 and keep the first and second bonding layers in close contact with each other 11 and 35. Since the first and second positioning holes 3411 and 3412 are already full, they cannot be inserted into the first and second positioning holes 3411. , 3412.

Through the above steps, three different colors of LED devices 101 , 102 , 103 can be embedded into their corresponding positioning holes and tightly attached to the corresponding pads, finally forming the colorized display 300 shown in FIG. 58 .

In addition, it should be noted that the specific embodiments described in this specification may have different names of each part, and any equivalent or simple changes made according to the structures, features and principles described in the patent concept of the present invention include within the protection scope of the patent of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or substitute in similar manners, as long as they do not deviate from the structure of the present invention or go beyond the scope defined by the claims, All should belong to the protection scope of the present invention.

Claims (41)

1. a manufacturing method of LED array device is characterized in that: A plurality of LED devices with vertical structures are provided, the inner side and the outer side of the LED devices are respectively provided with a first electrode and a second electrode, the first electrode is provided with a first magnetic part composed of a soft magnetic metal, and the first electrode is provided with a first magnetic part. the surface of the magnetic part is provided with a first bonding layer; Provide a motherboard, the outer side of the motherboard is a first board body surface, the first board body surface defines a plurality of bonding positions that form an array, and the bonding positions are provided with hard magnetic materials. the second magnetic portion; and, using the following processing steps: Step 1, setting a non-magnetic insulating base layer on the first plate body surface; Step 2: A driver circuit layer is arranged on the base layer, the driver circuit layer includes a plurality of pads and a driver circuit connected to the pads, the pads are located on the bonding position of the motherboard, at least Its surface is set as the second bonding layer; Step 3: Spread the LED device on the driving circuit layer, the first magnetic part of the first magnetic part is subjected to the force of the magnetic field of the second magnetic part on the pad, so that the LED device is positioned on the pad and the first magnetic part is adsorbed on the pad. A bonding layer is in close contact with the second bonding layer, wherein, the LED device is first dispersed into a liquid to form a dispersion liquid of the LED device, and then the dispersion liquid is brought into contact with the driving circuit layer, so that the LED in the dispersion liquid is the device is attached to the pad; Step 4, bonding the first bonding layer and the second bonding layer, so that the pad is electrically connected to the first electrode of the LED device; Step 5, separating the base layer and the motherboard from each other to obtain an LED array device. 2 . The manufacturing method of the LED array device according to claim 1 , wherein the first magnetic part is a soft magnetic metal layer composed of iron, nickel, manganese metal or an alloy thereof. 3 . 3. The method for manufacturing an LED array device according to claim 1, wherein the thickness of the first magnetic portion is 1˜200 μm. 4 . The manufacturing method of the LED array device according to claim 1 , wherein the first magnetic part is biased to a position inside the LED device. 5 . 5 . The manufacturing method of the LED array device according to claim 4 , wherein the thickness of the first magnetic portion does not exceed 1/2 of the overall thickness of the LED device. 6 . 6 . The manufacturing method of the LED array device according to claim 4 , wherein a non-magnetic metal layer is further cushioned between the first magnetic part and the first electrode. 7 . 7 . The manufacturing method of the LED array device according to claim 4 , wherein the thickness of the first bonding layer does not exceed 1/2 of the thickness of the first magnetic portion. 8 . 8. The manufacturing method of the LED array device according to claim 1, wherein the first bonding layer is a low melting point metal layer. 9 . The manufacturing method of the LED array device according to claim 1 , wherein the motherboard is a non-magnetic metal plate. 10 . 10 . The manufacturing method of the LED array device according to claim 1 , wherein the second magnetic part is made of AlNiCo permanent magnet alloy, FeCrCo permanent magnet alloy, permanent magnet ferrite, rare earth permanent magnet. 11 . Magnetic material or composite hard magnetic material composed of the above materials. 11. The manufacturing method of the LED array device according to claim 1, wherein the second magnetic part is made of a neodymium iron boron alloy. 12 . The manufacturing method of the LED array device according to claim 1 , wherein the bonding position of the motherboard is provided with an accommodating hole, and the second magnetic portion is embedded in the accommodating hole. 13 . 13 . The manufacturing method of the LED array device according to claim 12 , wherein the accommodating hole is formed on the first body surface of the motherboard by a process method of laser engraving, mask etching or mask electrolysis. 14 . 14. The manufacturing method of the LED array device according to claim 12, wherein: the accommodating holes of the mother board are filled with powder of the hard magnetic material, and the mother board is subjected to high temperature treatment, so that the hard magnetic material in the accommodating holes is The powder is sintered into the second magnetic part. 15. The manufacturing method of the LED array device according to claim 14, wherein the receiving hole is a through hole. 16 . The manufacturing method of the LED array device according to claim 14 , wherein the motherboard is made of a non-magnetic metal with a melting point greater than 1500° C. 16 . 17. The manufacturing method of the LED array device according to claim 12, wherein after the second magnetic part is arranged on the motherboard, polishing treatment and viscosity reduction treatment are performed on the first body surface of the motherboard. 18. The manufacturing method of the LED array device of claim 1, further comprising magnetizing the second magnetic portion. 19 . The manufacturing method of the LED array device according to claim 18 , wherein the second magnetic part is magnetized between the second step and the third step. 20 . 20 . The method for manufacturing an LED array device according to claim 1 , wherein the base layer is an organic film layer that is insulating, non-magnetic and has anti-stretching properties. 21 . 21. The manufacturing method of the LED array device according to claim 20, wherein the base layer is a polyimide film. 22. The method for manufacturing an LED array device according to claim 1, wherein in the driving circuit layer, the pitch of the pads is 1.2 to 5.0 times the size of the LED device. 23. The manufacturing method of an LED array device according to claim 1, wherein the second bonding layer is a metal layer with a low melting point. 24. The manufacturing method of an LED array device according to claim 1, wherein a positioning layer is further provided on the driving circuit layer, and the positioning layer is made of an insulating material and has a thickness of the LED device. 0.6 to 2.0 times the height, the positioning layer includes positioning holes corresponding to the bonding positions. 25. The method for manufacturing an LED array device according to claim 24, wherein the size of the positioning hole is 1.1 to 1.5 times the size of the LED device. 26 . The manufacturing method of the LED array device according to claim 24 , wherein the positioning layer is a photosensitive resin coating, and the positioning holes are made by a yellow light process. 27 . 27. The manufacturing method of an LED array device according to claim 24, wherein the positioning layer is a silicone coating, a polyimide coating or a high temperature resistant ink layer, and the positioning hole is formed by a laser engraving process , mask etching process or micro-nano imprinting process. 28. The manufacturing method of an LED array device according to claim 24, wherein the positioning hole is circular, and the LED device has a circular outline. 29. The manufacturing method of the LED array device according to claim 24, wherein: The LED device at least includes a first LED device, a second LED device, and a third LED device with decreasing sizes in sequence, and the first LED device, the second LED device, and the third LED device have different light-emitting colors; The positioning hole at least includes a first positioning hole, a second positioning hole and a third positioning hole with decreasing sizes in sequence, and the sizes of the first positioning hole, the second positioning hole and the third positioning hole are respectively the first LED device, 1.1 to 1.5 times the second LED device and the third LED device; and, In step 3, the first LED device, the second LED device and the third LED device are scattered on the driving circuit layer in sequence, so that the first LED device, the second LED device and the third LED device are embedded in the first LED device in sequence in the opening, the second opening and the third opening. 30. The manufacturing method of an LED array device according to claim 29, wherein the adjacent ratio of the size of the first, second and third LED devices is 1.6˜2.0. 31. The method for manufacturing an LED array device according to claim 24, wherein: a filling layer is covered on the positioning layer, and the filling layer penetrates and fills up the gap between the LED device and the positioning layer; The filling layer is cured and patterned to form exposed openings exposing the second electrode of the LED device; and a top conductive layer is disposed on the filling layer and the exposed opening to form the second electrode connection of the LED device. 32. The manufacturing method of the LED array device according to claim 31, wherein the filling layer is an ink layer. 33. The manufacturing method of the LED array device according to claim 31, wherein the filling layer is a photosensitive resin coating. 34. The manufacturing method of the LED array device according to claim 33, wherein the filling layer is a dark photosensitive resin coating. 35. The method for manufacturing an LED array device according to claim 1, wherein in the third step, a removal mechanism is further provided to remove the LED devices with poor adsorption or poor position. 36. The manufacturing method of the LED array device according to claim 35, wherein the cleaning mechanism is to use liquid or gas to wash the surface of the driving circuit layer. 37. The manufacturing method of an LED array device according to claim 35, wherein the cleaning mechanism is to apply mechanical vibration on the motherboard to shake off the poorly adsorbed or poorly positioned LED devices. 38. The manufacturing method of an LED array device as claimed in claim 35, wherein the removal mechanism is to apply a reverse magnetic field on the outer side of the motherboard, so as to absorb the poorly adsorbed or poorly positioned LED devices. Lose. 39. The manufacturing method of an LED array device according to claim 35, wherein the removal mechanism is to apply an adhesive on the outer side of the motherboard to stick off the poorly adsorbed or poorly positioned LED devices . 40. The manufacturing method of the LED array device according to claim 1, wherein after step 4, a top conductive layer is further covered on the second electrode to form the second electrode connection of the LED device. 41. The manufacturing method of an LED array device according to claim 40, wherein the top conductive layer is a transparent conductive film or a non-transparent conductive film partially in contact with the second electrode.

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