WO2019013469A1 - Micro-led display and manufacturing method therefor - Google Patents

Abstract

The invention relates to a micro-LED display. The display according to the invention comprises: a printed circuit board comprising a plurality of solder pads; a micro-LED package containing a plurality of micro-LED chips; and a plurality of solder electrodes for connecting the micro-LED chips to the solder pads of the printed circuit board. The micro-LED package can be rearranged to an RGB state on a temporarily fixed film using a pickup device, in accordance with a display pixel configuration, after the micro-LED chips are attached to a carrier film.

Description

Micro-LED display and its manufacturing method

Various embodiments of the invention relate to a micro-LED display and a method of making the same.

As a new display to replace LCD panels, OLED panels are in the spotlight, but high cost, large size, and reliability issues still remain as low production yields. Researches have been made on a technology to make a display panel by directly mounting an LED emitting a color of R (red), G (green), or B (blue) as a new product to be complemented.

However, in order to realize a display, it is necessary to develop a micro-LED (micro-LED) capable of corresponding to a current pixel, and to pick up a micro-LED having a size of several tens of micrometers, The problem of how to place the input / output terminals and electrically connect them to the main printed circuit board must be solved in advance.

In the case of a display using an LED package, it is inappropriate to apply it to a near-field display because the LED LED package is basically a size of several millimeters. The size of one pixel in a home display is usually about 100 mu m, and the size of R / G / B subpixel constituting it is only several tens of mu m.

Recently, it has been shown that LED chips of several tens of micrometers in size can be mass produced. However, it is not possible to pick up micro LED chips on a printed circuit board with the current pickup technology, As the area of the connecting pad decreases, precision mounting technology is required within a few micrometers of the micro-LED chip and the printed circuit board, but it is difficult to implement it as a display with the present technology.

For example, a 4K UHD class display panel requires about 25 million micro LEDs, requiring 2500 repairs at 99.99% (100 ppm) yield control, and a micro LED chip mounted at several tens of micrometers apart It is currently impossible to implement a technique that can be removed and re-implemented individually.

Conventionally, the solder balls are directly attached on the pads of the wafer, but due to the increase of the degree of integration, the intervals between the pads become dense, and short-circuiting between neighboring solder balls may occur.

Further, as the micro-LED chips are stacked, it is necessary to extend the pad formed at the center of the chip to the edge, for example. Therefore, it is necessary to rewire the connection terminals to the outside, that is, the positions where the solder balls are attached, by metal wiring.

In various embodiments of the present invention, a micro-LED array package is fabricated through a PLP rewiring process, a printed circuit board is fabricated through a TFT process, and a micro-LED array package and a printed circuit board are connected by a thermal compression process And to provide a micro-LED display.

The various embodiments of the present invention are capable of checking the performance of the micro-LED array package so that the micro-LED array package can be connected to another micro-LED chip and the printed circuit board after the micro LED array package is removed or regenerated and reworked. And an improved micro-LED display.

Various embodiments of the present invention provide a micro-LED display having a micro-LED array package manufactured through a PLP rewiring process, a printed circuit board fabricated through a TFT process, and laminated to have input / output terminals having a higher directivity .

A micro-LED display according to various embodiments of the present invention includes a printed circuit board including a plurality of solder pads, a micro-LED package including a plurality of micro-LED chips, and a micro- The micro-LED package may be attached to the carrier film and then rearranged in the RGB state on the temporary fixing film using a pickup device according to the display pixel configuration .

The manufacturing method according to various embodiments of the present invention includes a first step of attaching each of the micro-LED chips to a carrier film in a pad-down fashion, a step of attaching the attached micro-LED to the display pixel component A third step of molding the rearranged micro-LEDs, and a fourth step of performing the FOPLP (Fan-out panel level package) process on the molded micro-LEDs A micro LED display according to various embodiments of the present invention includes a micro LED array package and a TFT structure and includes a main printed circuit board laminated on the micro LED array package, And the micro-LED array package and the printed circuit It may comprise a member for supporting a connection between the plates.

In various embodiments of the present invention, a micro-LED array package is manufactured through a PLP rewiring process, and a printed circuit board is manufactured through a TFT process and laminated. Thus, an input / output terminal structure with a higher degree of directivity is possible, And the yield was improved.

The various embodiments of the present invention are capable of checking the performance of the micro-LED array package so that the micro-LED array package can be connected to another micro-LED chip and the printed circuit board after the micro-LED array package is removed or regenerated and reworked, .

The various embodiments of the present invention can be mounted on a substrate at a high yield with ease by utilizing a commercially available mount or the like, by making a micro-LED which is difficult to handle as a part.

The various embodiments of the present invention can easily repair the rework of tiny parts that have not yet been secured in the repair of the poorly mounted parts with the pre-established techniques.

FIGS. 1A to 1J are sectional views sequentially showing a method of fabricating a micro-LED display according to various embodiments of the present invention.

FIG. 2 is an exemplary view schematically showing a process of rearranging micro-LEDs according to various embodiments of the present invention.

3A is a cross-sectional view illustrating a state in which a PR process is performed on a pad of a micro-LED chip according to various embodiments of the present invention.

FIG. 3B is a plan view showing a state in which a photosensitive material is applied to the pads of the micro-LED chip according to various embodiments of the present invention.

4A through 4K are cross-sectional views sequentially illustrating a method of fabricating a micro-LED display according to various other embodiments of the present invention.

Figure 5 is a top view of a display fabricated using a display fabrication method according to various embodiments of the present invention.

6 is a plan view illustrating a display of a large screen size incorporating a micro-LED display manufactured using a display manufacturing method according to various embodiments of the present invention.

7 is a cross-sectional view illustrating an insulating structure and a non-insulating structure formed in a micro-LED chip package according to various embodiments of the present invention.

8 is a view showing a state in which a common electrode formed in a micro-LED chip package according to various embodiments of the present invention is provided.

Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that this disclosure is not intended to limit the present disclosure to the particular embodiments, but includes various modifications, equivalents, and / or alternatives of the embodiments of the present disclosure. In connection with the description of the drawings, like reference numerals may be used for similar components.

In this document, the expressions " having, " " having, " " comprising, " or &Quot;, and does not exclude the presence of additional features.

In this document, the expressions "A or B," "at least one of A or / and B," or "one or more of A and / or B," etc. may include all possible combinations of the listed items . For example, "A or B," "at least one of A and B," or "at least one of A or B" includes (1) at least one A, (2) at least one B, (3) at least one A and at least one B all together.

The terms "first," "second," "first," or "second," etc. used in various embodiments may describe various components in any order and / or importance, Lt; / RTI > The representations may be used to distinguish one component from another. For example, the first user equipment and the second user equipment may represent different user equipment, regardless of order or importance. For example, without departing from the scope of the present disclosure, the first component may be referred to as a second component, and similarly, the second component may be named as the first component.

It is also possible that a component (eg, a first component) is "(operatively or communicatively coupled) / to" another component (eg, a second component) It is to be understood that when an element is referred to as being " connected to ", it is to be understood that the element may be directly connected to the other element or may be connected through another element (e.g., a third element). On the other hand, when it is mentioned that a component (e.g., a first component) is " directly connected " or " directly connected " to another component (e.g., a second component) It can be understood that there is no other component (e.g., a third component) between other components.

The phrase " configured to " as used herein is intended to encompass, depending on the context, for example, having the ability to be suitable for, The present invention may be used interchangeably with "designed to," "adapted to," "made to," or "capable of". The term " configured to (or configured) " may not necessarily mean specifically designed to be "specifically designed." Instead, in some circumstances, the expression "a device configured to" (Or set) to perform phrases A, B, and C. For example, a processor " configured (or configured) to perform phrases A, B, and C " (E. G., An embedded processor), or a generic-purpose processor (e. G., A CPU or application processor) capable of performing the operations by executing one or more software programs stored in the memory device.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the other embodiments. The singular expressions may include plural expressions unless the context clearly dictates otherwise. All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art of the present disclosure. Commonly used predefined terms may be interpreted to have the same or similar meaning as the contextual meanings of the related art and are not to be construed as ideal or overly formal in meaning unless expressly defined in this document . In some cases, the terms defined herein may not be construed to exclude embodiments of the present disclosure.

An electronic device in accordance with various embodiments of the present disclosure can be, for example, a smartphone, a tablet personal computer, a mobile phone, a videophone, an electronic book reader e- book reader, a desktop personal computer, a laptop personal computer, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP) Player, a mobile medical device, a camera, or a wearable device (e.g. smart glasses, head-mounted-device (HMD)), electronic apparel, electronic bracelets, electronic necklaces, An electronic device, an electronic device, an apparel, an electronic tattoo, a smart mirror, or a smart watch).

In some embodiments, the electronic device may be a smart home appliance. Smart home appliances include, for example, televisions, digital video disk players, audio, refrigerators, air conditioners, vacuum cleaners, ovens, microwaves, washing machines, air cleaners, set- (Such as a home automation control panel, a security control panel, a TV box, such as Samsung HomeSync ^TM , Apple TV ^TM or Google TV ^TM , a game console such as Xbox ^TM , PlayStation ^TM , An electronic key, a camcorder, or an electronic photo frame.

In an alternative embodiment, the electronic device may be any of a variety of medical devices (e.g., various portable medical measurement devices such as a blood glucose meter, a heart rate meter, a blood pressure meter, or a body temperature meter), magnetic resonance angiography (MRA) A global positioning system receiver, an event data recorder (EDR), a flight data recorder (FDR), an automotive infotainment device, a navigation system, a navigation system, Electronic devices (eg marine navigation devices, gyro compass, etc.), avionics, security devices, head units for vehicles, industrial or home robots, ATMs (automatic teller's machines) point of sale or internet of things such as light bulbs, various sensors, electric or gas meters, sprinkler devices, fire alarms, thermostats, street lights, toasters, A water tank, a heater, a boiler, and the like).

According to some embodiments, the electronic device is a piece of furniture or a part of a building / structure, an electronic board, an electronic signature receiving device, a projector, Water, electricity, gas, or radio wave measuring instruments, etc.). In various embodiments, the electronic device may be a combination of one or more of the various devices described above. An electronic device according to some embodiments may be a flexible electronic device. Further, the electronic device according to the embodiment of the present disclosure is not limited to the above-described devices, and may include a new electronic device according to technological advancement.

Hereinafter, with reference to the accompanying drawings, a structure and a manufacturing method of a display using a micro-LED mounting technique according to various embodiments of the present invention will be described.

Since the structure of the display according to the present invention can be implemented regardless of the size of the LED, the size of the LED to be used is not limited. For example, a large-sized display such as an indoor / outdoor signage uses a few hundred micrometers of LEDs, and an LED of several tens of micrometers can be used for a display. have.

FIGS. 1A to 1I are sectional views sequentially illustrating a method of fabricating a micro-LED display according to various embodiments of the present invention.

Since the structure of the display according to the present invention can be implemented regardless of the size of the LED, the size of the LED to be used is not limited. For example, a large-sized display such as an indoor / outdoor signage uses a few hundred micrometers of LEDs, and an LED of several tens of micrometers can be used for a display. have.

The size of the micro-LED chip referred to in the present invention may refer to a micro-LED chip having a size of less than 100 micrometers, for example, a size of 1 to 99 micrometers.

Referring to FIG. 1A, a micro-LED 102 is grown on a sapphire or SiX substrate 100 in a single crystal state of a compound semiconductor under a high-temperature / high-pressure state, and may be formed in different colors depending on each composition.

For example, red is composed of GaAs, green is composed of InGaP, and blue is composed of compound semiconductors of GaN. The wavelengths are determined according to the intrinsic energy bandgap values of the respective compositions, and the implemented colors may appear differently.

In order for the grown microelectrode wafer to emit light, it is subjected to several tens of semiconductor processes in an electrically connectable structure in which holes and electrons can be supplied. In this case, the pad 102a of the micro-LED 102 may be fabricated in a vertically upward direction of the sapphire substrate 100.

Referring to FIG. 1B, the manufactured micro-LEDs 112 may be separated into a plurality of cells by a singulation and a flipping process. The separated micro LEDs may be referred to as micro LED chips 112. Each micro-LED chip 112 may be attached in an aligned state on a carrier film or a transfer film.

As a method of attaching the manufactured micro-LED 112 to the carrier film 110, a method using an uncured resin (liquid poly (PI), polydimethylsiloxane (PDMS), polyethylene terephthalate (PET) At least one of the methods utilizing the difference in adhesion between a UV-curable tape (UV-tape) and a non-UV tape or a film-type tape such as a heat-foam tape can be used.

Referring to FIG. 1C, a plurality of micro-LED chips (R / G / B) that are attached in an aligned fashion include elements constituting a display pixel, such as pitch, color (R / G / B) And may be rearranged on the temporary fixing film 122 in accordance with a gap or the like.

Hereinafter, the micro-LED chips will be referred to as R, G, and B, respectively. R represents a micro-LED chip emitting red color, G represents a micro-LED chip emitting green color, and B represents a micro-LED chip emitting blue color.

For example, a method of rearranging a plurality of micro-LED chips R / G / B is performed by using a pickup tool or picker 125 for each micro LED chip R / G / The micro-LED chip can be picked up and fixed on the temporary fixing film 122.

The method of rearranging the plurality of micro-LED chips R / G / B is a method of picking up the micro-LED chips R / G / B and transferring them to a temporary fixing film, (R / G / B) is picked up and fixed on a temporary fixing film, or a method of picking up a micro-LED chip (R / G / B) using a magnetic field and fixing it on a temporary fixing film, (R / G / B) is picked up and fixed on a temporary fixing film by using a micro-LED chip (R / G / B) Any of which may be applied.

After the aligned micro LIs emitting blue light, the aligned micro LIs emitting green light and the micro LIs emitting red light are prepared, (R / G / B) selected by the R / G / B can be moved and rearranged on the temporary fixing film 122. Arrow directions (?,?,?) Indicate the moving direction of the pickup device 125. The moving direction of the pick-up device 125 moves the selected micro LED chip R / G / B vertically upward (①), horizontally moves (②), vertically downward (③) The micro-LED chip (R / G / B) can be rearranged by being placed on the temporary fixing film 122. The shifted microLED chip (R / G / B) can be fixed in a state in which RGB is rearranged into one set. The temporary fixing film 122 may be adhered to and transported to the carrier film. Thereafter, the micro-LED chips attached on the temporary fixing film 122 are formed in a board form by a molding process and can be fixed by a molding portion.

Referring to FIG. 1D, rearranged micro-LED chips (R / G / B) according to various embodiments are formed in a board form by a molding process and can be fixed by the molding part 130. For example, a transfer molding, an injection molding, a compression molding, or the like may be used as a method of molding in the form of a board. The molding material may be an epoxy resin or a Si resin. As will be described later, a plurality of aligned micro-LED chips (R / G / B) are molded into a board shape by a molding process, so that electrical connection or physical connection with a printed circuit board .

Each of the molded micro-LED chips (R / G / B) can be fixed to the temporary fixing film 122 and can be arranged in a board form. The rearranged micro-LEDs (R / G / B) can be prepared in a rigid board form by the molding part 130. For example, each of the micro-LED chips R / G / B can be fixed with a certain interval by the molding part 130, and the micro-LED chips R / G / .

Referring to FIG. 1E, micro-LED chips (R / G / B) according to various embodiments can be peeled off from the temporary fixing film 122 by the LLO process. The LLO process can separate the micro-LED chips (molding portion 130) and the temporary fixing film 122 by irradiating a laser. Each separated micro LED chip (R / G / B) can be exposed to the connection pad.

Referring to FIG. 1F, stripped micro-LED chips (R / G / B) according to various embodiments may be disposed on the printed circuit board 140. For example, one side of the printed circuit board 140 and one side of the molding part 130 may be joined. One surface of the molding part 130 may be a surface on which the connection pads of the respective micro-LED chips R / G / B are exposed.

Referring to FIG. 1G, a printed circuit board 140 according to various embodiments may be subjected to a FOPLP process to form a circuit 142 (electrical connection path). That is, the circuit (wiring) 142 formed on the printed circuit board 140 is electrically connected to the pad p of each micro LED chip R / G / B by the conductive material 141 formed by the via 140a And can be electrically connected.

The FOPLP process includes the steps of forming a via 140a (Via) on the lower surface of the printed circuit board 140 using a laser, and forming the via 140a using a plating process to form a conductive material 141 And forming a circuit 142 through a photolithography process after the bottom surface of the printed circuit board 140 is subjected to frontal plating deposition. The printed circuit board 140 having undergone such a process can be referred to as a redistributing printed circuit board. For example, as the laser forming the via 140a, either a CO ₂ laser or an IR laser can be used. For example, in the plating process, the conductive material 141 filling the via 140a may include any one of Cu, Sn, a Sn-Ag alloy, and a Sn-Ag-Cu alloy.

Referring to FIG. 1H, the printed circuit board 140 on which the FOPLP process according to various embodiments is performed may further have a conductive structure on a lower surface, for example, a surface on which the circuit is formed. The conductive structure may be formed to electrically connect the micro-LED chips (R / G / B) to a main printed circuit board (not shown).

The conductive structure according to various embodiments may include at least one solder electrode 150 (e.g., solder ball) formed by a soldering process. For example, the solder electrode 150 may be formed to electrically connect to a connection pad of a main printed circuit board, which will be described later. Micro-LED chips (R / G / B) according to various embodiments can be parted by sigaling to a certain size. Micro-LED chips fabricated in this manner can be referred to as a micro-LED array package 14. A micro-LED array package 14 prepared in Fig. 1H is shown.

The micro-LED array package 14 according to various embodiments includes a plurality of micro-LED chips (R / G / B) arranged at regular intervals in order to facilitate connection with a printed circuit board (e.g., Lt; / RTI > Also, the molded micro-LED chips (R / G / B) can be arranged in a board form, so that connection with the printed circuit board can be facilitated.

The micro-LED array package 14 according to various embodiments may have a structure of insulation or non-insulation material between the micro-LED chips (R / G / B) to prevent the gap between the micro- Can be additionally configured. Such a structure can be molded integrally with the micro-LED chips (R / G / B) in the molding process.

As the structure according to various embodiments, a photosensitive polymer material using a photoresist or the like may be used, and a metal formed by a method such as etching or plating may be used.

The micro-LED array package 14 according to various embodiments may be configured such that the size of the bonding pad is expanded by using an insulation and rewiring process for ease of connection with a printed circuit board (e.g., 160 of FIG. .

The micro-LED array package 14 according to various embodiments may include a common electrode of a micro-LED chip (R / G / B) for ease of connection with a printed circuit board (e.g., 160 of FIG. The number of bonding pads to be bonded can be reduced. For example, the bonding pads may be formed with additional connecting members such as a solder bump, a copper post, etc. for ease of connection.

Referring to FIGS. 1I and 1J, a prepared micro-LED array package 14 according to various embodiments may be laminated to a printed circuit board 160 by a heat treatment process using a member 170. For example, the micro-LED array package 14 may be electrically connected to the printed circuit board 160 physically and integrally by the heat treatment process.

The printed circuit board 160 according to various embodiments may be a substrate having a TFT structure. For example, the printed circuit board 160 can be manufactured by a process of making a transistor capable of controlling each pixel. A printed circuit board 160 having a TFT structure is formed by supplying a desired voltage to a pixel at a time when the switch is turned on and then applying a voltage to the active element 160 to maintain the desired voltage until the next time the pixel is completely isolated, Lt; / RTI > For example, the printed circuit board 160 on which the TFT structure is formed can utilize a substrate material that is easy to form high-temperature TFTs such as ceramic, glass, and silicon. A plurality of vias 160a may be formed on the printed circuit board 160. The formed vias 160a may be filled with a conductive paste such as copper paste or silver paste to withstand a high temperature TFT process.

In a printed circuit board 160 having a TFT structure according to various embodiments, a separate polyimide film for supporting a high-temperature TFT process and a polyimide film laminated with a polyimide film to form a relatively low- The printed circuit board 160 can be utilized.

In order to secure the warpage and flatness of the printed circuit board 160 on the printed circuit board 160 formed by joining polyimide, as an example of the substrate material to be additionally laminated, not only general materials such as FR4 and BT, but also RCC And can be configured to add structural board materials such as glass, ceramic, and chassis.

The printed circuit board 160 according to various embodiments may include a first surface 160a on which each connection pad 161 is exposed and a second surface 160b opposite to the first surface 160a. And the other surface 160b may be disposed such that the other end of the conductive material portion 162 electrically connected to the connection pad 161 is exposed. And the second conductive structure 180 may be formed at the other end portion. For example, the second conductive structure 180 may include at least one solder electrode (e.g., solder ball) formed by a soldering process. For example, the printed circuit board 160 may be packaged by forming a second conductive structure 180 thereon. The second conductive structure 180 may be configured in a different shape than the first conductive structure 150.

The member 170 according to various embodiments is a member for connecting the micro-LED array package 14 and the printed circuit board 160. The member 170 may be formed by heat treatment between the printed circuit board 160 and the micro- It can be formed to be filled with fullness. The member 170 before the heat treatment is shown in FIG. 1I, and the member 170 after the heat treatment is shown in FIG. 1J.

In addition, the post-heat-treated member 170 can support the connection state between the micro-LED array package 14 and the printed circuit board 160. For example, the member 170 may fill between the first conductive structures 150 between the micro-LED array package 14 and the printed circuit board 160.

The member 170 according to various embodiments may be attached to one side of the printed circuit board 160 by coating or laminating prior to heat treatment. The member 170 may be melted after the heat treatment process so as to completely fill the space between the printed circuit board 160 and the micro-LED array package 14. [ For example, the member 170 may be a film made of a synthetic resin, or may be formed of a metal sheet of copper or the like and attached to the exposed connection pad of the printed circuit board 160 on one side 160a of the printed circuit board 160 The heat treatment may be performed.

The heat treatment process according to various embodiments is a thermal pressure (shaft) bonding process, and the micro-LED array package 14 may be integrally attached to the printed circuit board 160 using the thermal compression bonding process. In addition, the heat treatment process includes an ultrasonic welding process and a heat melting process, and the micro-LED array package 14 may be integrally mounted on the printed circuit board 160 using a thermal compression bonding process.

Each pad P of the micro-LED chip R / G / B according to various embodiments is electrically connected to the solder pad 161 of the printed circuit board 160 by the first conductive structure 150, The solder pad 161 may be electrically connected to the second conductive structure 180 through the conductive material portion 162.

In a final step, the component micro-array array package 14 may be fabricated as a display on the printed circuit board 160, and may be manufactured as a display of various sizes.

FIG. 2 is an exemplary view schematically showing a process of rearranging micro-LEDs according to various embodiments of the present invention.

Referring to FIG. 2, a plurality of micro-LEDs (R / G / B) that are attached in an aligned manner may include elements constituting a display pixel, such as pitch, color (R / G / B) And can be rearranged on the substrate 220. [ 1C, a plurality of micro-LEDs (R / G / B) are directly rearranged on the temporary fixing film 122. In FIG. The process of heating will be described below.

2 shows a process of rearranging the micro-LEDs (R / G / B) on the substrate 220 by using the pickup device 225. After the aligned micro LIs (B) emitting blue light, the aligned micro LIs emitting green color and the micro LIs emitting red color are prepared, Lt; RTI ID = 0.0 > 220 < / RTI > The arrow direction (2) indicates the moving direction of the pickup device 225. The shifted micro LED (R / G / B) can be arranged on the substrate in a rearranged arrangement of RGB as one set.

3A is a cross-sectional view illustrating a state in which a PR process is performed on a micro-LED chip (R / G / B) according to various embodiments of the present invention. FIG. 3B is a plan view showing a state in which a photosensitive material is applied to a micro-LED (R / G / B) according to various embodiments of the present invention.

Referring to FIGS. 3A and 3B, the PR process can be performed before the micro-LED chip (R / G / B) in the molded state, which is peeled off from the temporary fixing film according to various embodiments, is connected to the printed circuit board.

(R / G / B) supported by the molding part 230 after being separated from the temporary fixing film may be formed by a PR (photoresist) or SR (solder resist) process, . ≪ / RTI > The coated photosensitive material is applied in a predetermined area on the upper surface 230a in a layer shape so as to arrange a position with respect to the printed circuit board 230 and to observe the wiring state of each of the micro-LED chips R / G / B You can give. For example, the PR process may not be performed. Hereinafter, the applied photosensitive material will be referred to as a photosensitive layer.

Each of the photosensitive layers 222 according to various embodiments may be formed in an area enough to include each connection pad p of each micro-LED chip R / G / B. The respective connection pads p of the micro-LED chips R / G / B can be covered by the photosensitive layer 222. [

4A to 4K are cross-sectional views sequentially illustrating a method of fabricating a micro-LED display according to various other embodiments of the present invention. Referring to FIGS. 4A to 4K, a micro-LED mounting technique according to various embodiments of the present invention A method of producing a display using the display device will now be described.

Referring to FIG. 4A, the micro LED 402 is grown on a sapphire substrate 400 in a single crystal state at a high temperature / high pressure. The micro LED 402 may have a different composition depending on each color. As already described in detail in FIG. 1A, the detailed description will be omitted in order to avoid redundant description.

Referring to FIG. 4B, the prepared substrate 410 according to various embodiments may be coated with an uncured liquid material 412 on one side. For example, the uncured liquid material 412 according to various embodiments may be formed to have a predetermined thickness on one surface of the substrate in a layer shape. Hereinafter, the uncured material that is applied is referred to as an uncured layer.

The substrate 410 according to various embodiments may be made of a glass material. The substrate 410 may have a layer shape and may be arranged so as to overlap with the uncured layer 412.

4C, after the uncured layer 412 coated on the substrate 410 is cured, the micro-LED (R / G / B) is peeled off from the sapphire substrate 400 through the LLO process, Micro-LED (R / G / B) can be arranged to be rearranged on the cured layer 412. The curing operation can be performed by irradiating ultraviolet rays to cure the uncured layer 412 to a rigid layer.

4D shows a micro-LED that has been rearranged and fixed on the substrate 410 according to various embodiments.

Referring to FIG. 4E, micro-LEDs (R / G / B) arranged on the substrate 410 according to various embodiments may be removed by gallium (Ga) etching by wet etching. Gallium (Ga) is a metal that exists in a liquid state at room temperature and remains partially on the separated LED layer during the laser lift-off (LLO) process. This is because the luminance of the LED is decreased, Molding process, etc.), it may be necessary to remove it. The wet etching process of gallium (Ga) can be performed after immersing in the aqueous solution of phosphoric acid (H ₃ PO ₄ ) or hydrochloric acid (HCl) in the vessel 420 for a certain period of time. The wet etching process may not be performed in the present invention.

Referring to FIG. 4F, a transfer molding method, an injection molding method, or the like is used for molding the rearranged micro-LED (R / G / B) according to various embodiments in a board form . For example, an epoxy-based or Si-based resin may be used as the molding material. The molded micro LED (R / G / B) may remain fixed to the substrate 410 and may be arranged in a board type. The rearranged micro-LEDs (R / G / B) can maintain a rigid board shape by the molding part 430. For example, the molding portion 430 may be black.

Referring to FIG. 4G, micro-LEDs (R / G / B) according to various embodiments may be peeled off the substrate 410 by the LLO process. The LLO process can separate the molding portion 430 and the substrate 410 by irradiating a laser.

4H and 4I, after the via 440a is formed in accordance with the pad position of the micro-LED (R / G / B) and the via 440a is filled with the conductive material 441, Can be implemented.

The FOPLP process includes the steps of forming a via 440a (Via) using a laser under the molding part 430 and forming the via 440a by a plating process using a conductive material 441 (e.g., copper And forming a circuit 445 through a photolithography process after the bottom surface of the layer 412 is subjected to front-surface plating deposition.

As the laser for forming the via 440a according to various embodiments, either a CO ₂ laser or an IR laser may be used. For example, the conductive material 441 filling the via 440a with plating may include any one of Cu, Sn, Sn-Ag alloy, and Sn-Ag-Cu alloy.

Referring to FIG. 4J, at least one solder electrode 450 (e.g., solder ball) may be formed on the bottom surface of the layer 412 on which the FOPLP process according to various embodiments is performed by a soldering process. For example, the solder electrode 450 may be formed to electrically connect a conductive material layer 445 to a solder pad of a main printed circuit board, which will be described later. Micro-LEDs (R / G / B) according to various embodiments can be singulated to a certain size and can be made into parts. The micro-LED (R / G / B) manufactured by this method can be referred to as a micro-LED package.

Referring to FIG. 4K, the micro-LED package according to various embodiments may be bonded to the pad 460a of the main PCB 460 of the solder electrode 450. The microelectrode pad can be electrically connected to the solder pad 460a of the main printed circuit board by the solder electrode 450. The micro-LED (R / G / B) having such a configuration can be at least a part of the display.

In the final step, the component micro-LED package (module) can be mounted on the main board and made into a display, and can be made into a display of various sizes.

A micro-LED display 500 manufactured through the manufacturing process shown in Figs. 1A to 1J is shown in Fig.

6 is a plan view showing a display of a large screen size incorporating a micro-LED display 610 manufactured using a display manufacturing method according to various embodiments of the present invention.

Referring to FIG. 6, a plurality of manufactured micro-LED displays 610 may be assembled to manufacture a micro-LED display 600 having a wider range of widths (for example, a large-sized TV, a theater display, etc.).

Referring to FIG. 7, the micro-LED array package 75 has micro-LED chips (R / G / B) aligned at regular intervals for ease of connection with a printed circuit board, An insulation structure 752 of water or a non-insulation structure 751 may be formed between the micro-LED chips (R / G / B) to prevent a deviation between the R / G / B. For example, the insulating structure 752 may be disposed between each of the micro-LED chips R / G / B, and may be disposed between the micro-LED chips composed of a set of RGB. In addition, the non-column array structure 751 may be disposed between the respective micro-LED chips (R / G / B) and arranged between the micro-LED chips composed of a set of RGB. For example, the non-insulating structure 751 may include barrier ribs made of a conductive material.

Referring to FIG. 8, the size of the connection pad P is extended using an insulation and rewiring process for ease of connection with the printed circuit board, and the micro LED chip R / G / B are connected and bonded to each other, the number of connection pads P can be reduced.

As used in this document, the term " module " may refer to a unit comprising, for example, one or more combinations of hardware, software or firmware. A " module " may be interchangeably used with terms such as, for example, unit, logic, logical block, component, or circuit. A " module " may be a minimum unit or a portion of an integrally constructed component. A " module " may be a minimum unit or a portion thereof that performs one or more functions. May be implemented mechanically or electronically. For example, a "module" may be an application-specific integrated circuit (ASIC) chip, field-programmable gate arrays (FPGAs) or programmable-logic devices And may include at least one.

According to various embodiments, at least some of the devices (e.g., modules or functions thereof) or methods (e.g., operations) according to the present disclosure may be stored in a computer readable storage medium -readable storage media). The instructions, when executed by one or more processors (e.g., the processor 210), may cause the one or more processors to perform functions corresponding to the instructions. The computer readable storage medium may be, for example, the memory 220. At least some of the programming modules may be implemented (e.g., executed) by, for example, a processor. At least some of the programming modules may include, for example, modules, programs, routines, sets of instructions or processes, etc. to perform one or more functions.

The computer-readable recording medium includes a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD (Digital Versatile Disc) A magneto-optical medium such as a floppy disk, and a program command such as a read only memory (ROM), a random access memory (RAM), a flash memory, Module) that is configured to store and perform the functions described herein. The program instructions may also include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of this disclosure, and vice versa.

A module or programming module according to the present disclosure may include at least one or more of the elements described above, some of which may be omitted, or may further include other additional elements. Operations performed by modules, programming modules, or other components in accordance with the present disclosure may be performed in a sequential, parallel, iterative, or heuristic manner. Also, some operations may be performed in a different order, omitted, or other operations may be added.

It is to be understood that the various embodiments of the present disclosure disclosed in this specification and the drawings are only illustrative of specific examples in order to facilitate describing the subject matter of the disclosure and to facilitate understanding of the disclosure, and are not intended to limit the scope of the disclosure. Accordingly, the scope of the present disclosure should be construed as being included within the scope of the present disclosure in addition to the embodiments disclosed herein, all changes or modifications derived from the technical idea of the present disclosure.

Claims (16)

In a micro-LED display, A printed circuit board comprising a plurality of solder pads; A micro-LED package including a plurality of micro-LED chips; And And a plurality of solder electrodes for bonding the micro-LED chips on the solder pads of the printed circuit board, The micro- Wherein each of the micro-LED chips is attached to a carrier film and rearranged in an RGB state on a temporary fixing film using a pickup device in accordance with the display pixel configuration. The method of claim 1, wherein the rearranged micro-LED chips are arranged in a board form by a molding portion, Each pad of the board-type micro-LED chips A micro-LED display is arranged to be electrically connected to a substrate on which circuits are formed. 3. The method of claim 2, wherein a photosensitive material is applied to the connection pads of the micro-LED chips arranged in the form of a board, A micro-LED display for holding a connection position between the micro-LED chip and the substrate and shielding a wiring state of the micro-LED chips. A method of manufacturing a micro-LED display, A first step of attaching each of the micro-LED chips to a carrier film in a pad-down fashion; A second step of rearranging the attached micro-LEDs on the temporary fixing film using a pickup device in accordance with the display pixel component;  A third step of molding the rearranged micro-LEDs; And And a fourth step of performing a FOPLP (Fan-out panel level package) process on the molded micro-LED.  5. The method according to claim 4,  After removing the temporary fixing film from the molded micro-LED, the micro-LED is bonded to the substrate, the FOPLP process is performed on the substrate, In the FOPLP process, Forming a via in a lower portion of the substrate using a laser; Filling the via with a conductive material using a plating process; And And forming a circuit through a photolithography process after plating the lower surface of the substrate by plating.  6. The method of claim 5, further comprising, after the fourth step,  A fifth step of forming a solder electrode on the connection pad of the micro-LED;  A sixth step of singulating the micro-LED formed with the solder electrode into a package of a predetermined size; And  And a seventh step of mounting the package of the micro-LED on a main printed circuit board to manufacture a display. 5. The method of claim 4, wherein the first step A laser lift-off (LLO) process for separating the sapphire substrate from the micro-LED by irradiating laser light onto the micro-LED attached to the sapphire substrate, Further comprising, after the third step, peeling the molded micro-LED from the temporary fixing film into the LL0 process. The method according to claim 7, further comprising a wet etching process in which the sapphire substrate is immersed in a liquid metal (H3PO4) Wherein the wet etching process removes gallium. In a micro-LED display, A micro-LED array package; A main printed circuit board having a TFT structure and being laminated to the micro-LED array package; And And a member formed between the micro-LED array package and the printed circuit board to support a connection state between the micro-LED array package and the printed circuit board. The micro-array array package according to claim 9, wherein each of the micro-LED chips is aligned at regular intervals for easy connection with the printed circuit board, and the micro- Micro-LED displays that include isolated or non-insulated structures. The micro-LED display according to claim 10, wherein the structure is formed of a photosensitive molybdenum material using photoresist, or a metal is used by a method of etching or plating. The micro-LED display according to claim 9, wherein the supporting member is made of a metal sheet made of copper or a film made of synthetic resin, and is attached on the exposed connection pad of the printed circuit board. 10. The method of claim 9, wherein the micro-LED array package and the printed circuit board are connected by a thermal process using the member, Wherein the thermal process includes any one of a thermal pressure bonding process, an ultrasonic fusion process, and a thermal melting process, and the printed circuit board is mounted with the micro-LED array package integrally using the thermal process. 10. The micro-LED display of claim 9, wherein the member is formed of a conductive paste comprising copper paste, Ag paste to withstand a high temperature TFT process. The method of claim 9, wherein the printed circuit board having the TFT structure comprises a polyimide film to withstand a high temperature TFT process, and a substrate having a relatively low-temperature via formed by bonding the polyimide film, Micro-LED display. 16. The method of claim 15, wherein after the polyimide film is laminated, the resin may be built up using resins including FR4, BT, and RCC in order to secure the warp and flatness of the substrate, Wherein the substrate is made of a material selected from the group consisting of glass, ceramics, and ceramics.

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