KR102486735B1 - Micro LED Package and Method for Manufacturing Thereof - Google Patents

Abstract

A micro LED package and a method for producing the same are disclosed.
According to one aspect of this embodiment, in the method of manufacturing a fine LED package, manufacturing a TFT including a bonding electrode, a rear electrode disposed on the opposite side of the bonding electrode, and a bump disposed on the bonding electrode A deposition process of depositing a micro LED including a fabrication process and bonding electrode on a temporary substrate, a bonding process of bonding the bonding electrode of the micro LED to the bump of the TFT, and an underfill between the micro LED and the TFT An underfill process for separating the micro LEDs from the temporary substrate, a separation process for separating the micro LEDs from the temporary substrate, a passivation process for passivating the micro LEDs separated from the temporary substrate, and dicing to include one micro LED and the TFT to include one micro LED. Provided is a micro LED package production method comprising a generating process of generating a package and a moving process of moving each micro LED package generated in the generating process to a counter substrate, respectively.

Description

Micro LED package and its production method {Micro LED Package and Method for Manufacturing Thereof}

The present invention relates to a micro-sized LED package such as a micro LED and a method for producing the same.

The contents described in this part merely provide background information on the present embodiment and do not constitute prior art.

As a recently emerging display technology, there is a micro LED. As a display panel manufactured using fine-sized RGB LEDs, it is in the spotlight because it is small, has high response speed and high brightness, and consumes low power.

In the method of producing such a micro LED, a conventional COB (Chip on Board) method has been used. The COB method is a method in which each fine RGB LED is directly placed on a control board such as a TFT or PCB and wire bonding is performed. Due to the relatively simple production method, it is widely used because it has excellent characteristics in terms of time and cost.

Conventionally, one control device (TFT or the like) controls the RGB LED disposed on the control board. The problem lies in that the size of the LEDs becomes smaller and the number of LEDs disposed on the control board increases. Since numerous fine-sized LEDs are disposed on the control board, it takes a long time for the control device to control each individually.

Accordingly, there is an increasing demand for micro-LEDs in which a pixel-driven driver for driving each of the micro-LEDs disposed on the control board is incorporated.

An object of one embodiment of the present invention is to provide a micro LED package including a driving driver in a micro-sized LED and a method for producing the same.

According to one aspect of the present invention, in the method of manufacturing a micro LED package, manufacturing a TFT including a bonding electrode, a rear electrode disposed on the opposite side of the bonding electrode, and a bump disposed on the bonding electrode A deposition process of depositing a micro LED including a fabrication process and bonding electrode on a temporary substrate, a bonding process of bonding the bonding electrode of the micro LED to the bump of the TFT, and an underfill between the micro LED and the TFT An underfill process for performing an underfill process, a separation process for separating the micro LED from the temporary substrate, a passivation process for depositing a coating thin film on the micro LED separated from the temporary substrate, and a dicing process so that the micro LED and the TFT are included one by one. Provided is a micro LED package production method comprising a production process of generating an LED package and a transfer process of moving each micro LED package generated in the production process to a counter substrate, respectively.

According to one aspect of the present invention, the fine LED is characterized in that implemented as a flip chip (Flip Chip).

According to one aspect of the present invention, the bonding process is characterized in that the bonding electrode of the fine LED is bonded to the bump of the TFT using a laser reflow (Laser Reflow).

According to one aspect of the present invention, a TFT including a bonding electrode, a rear electrode disposed on the opposite side of the bonding electrode, and a bump disposed on the bonding electrode, and a bonding electrode bonded on the bump of the TFT, It provides a fine LED package, characterized in that it comprises a fine LED forming one package with the TFT.

According to one aspect of the present invention, the fine LED is characterized in that implemented as a flip chip (Flip Chip).

According to one aspect of the present invention, the fine LED is characterized in that it is bonded on the bump of the TFT using a laser reflow (Laser Reflow).

As described above, according to one aspect of the present invention, by producing a micro-LED package including a driving driver in a micro-sized LED, there is an advantage in that the micro-LED can be quickly and easily controlled.

1 is a diagram illustrating a fine LED package according to an embodiment of the present invention.
2 to 7 are diagrams illustrating a process of manufacturing a micro LED according to an embodiment of the present invention.
8 to 12 are diagrams illustrating a process of fabricating a TFT according to an embodiment of the present invention.
13 to 16 are diagrams illustrating a process of manufacturing a micro LED package by combining a micro LED and a TFT manufactured according to an embodiment of the present invention.
17 is a flowchart illustrating a method of producing a micro LED package according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention. Like reference numerals have been used for like elements throughout the description of each figure.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no intervening element exists.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. It should be understood that terms such as "include" or "having" in this application do not exclude in advance the possibility of existence or addition of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. .

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

1 is a diagram illustrating a fine LED package according to an embodiment of the present invention.

Referring to FIG. 1 , a micro LED package 100 according to an embodiment of the present invention includes a micro LED 110 and a TFT 120 .

The fine LED 110 emits light by itself without a color filter. The micro LED 110 refers to a subminiature LED that generates and outputs light of a desired color by itself without a color filter for generating colors. Fine LED 110 has a representative micro (Micro) LED.

The TFT 120 is disposed below the fine LED 110 and is connected to the counter substrate 130 to control each of the fine LEDs 110 . Within the micro LED package 100, a TFT 120 is disposed on the bottom of each micro LED 110 (eg, which can be any of a micro R LED, a micro G LED, or a micro B LED) such that each micro LED Controls the operation of (110). As the TFTs 120 for controlling the fine LEDs 110 are disposed in each of the fine LED packages 100, the fine LED package 100 can more easily control each of the fine LEDs 110, and more Each fine LED 110 can be quickly controlled.

A fine LED package 100 is fabricated and transferred onto a counter substrate 130 , in particular, a solder 135 .

The counter substrate 130 includes solder 135 on its surface.

The solder 135 is an alloy used for soldering, etc., and serves as an electrode that is connected to the electrode of the fine LED package 100 to supply power. For example, the solder 135 may be implemented with an alloy such as AgSn or SnAgCu. At the same time, the solder 135 may have higher adhesive strength than that of the film or temporary sheet. When the fine LED package 510 approaches or contacts the solder 135 , the fine LED package 510 is separated from the grown film or temporary sheet so that it can be transferred to the solder 135 .

The solder 135 is disposed on the counter substrate 130 at each position where the fine LED package 510 is to be transferred. Typically, since the plurality of fine LED packages 100 are transferred to the counter substrate 130 at regular intervals, the corresponding solder 135 is also disposed on the counter substrate 130 at regular intervals. In addition, the solder 135 is disposed as many as the number to be connected to the electrode of each TFT 120 included in the fine LED package 100.

The solder 135 may be implemented in the form of a solder ball.

2 to 7 are diagrams illustrating a process of manufacturing a micro LED according to an embodiment of the present invention.

Referring to FIG. 2 , a light emitting layer growth process of growing light emitting layers 210 and 220 for light emission on a temporary substrate 230 is performed. Here, the light emitting layers 210 and 220 may be implemented with gallium nitride (GaN), but are not necessarily limited thereto, and may be implemented with various materials depending on the color to be emitted by the micro LED or the size of the micro LED to be manufactured. .

Referring to FIG. 3 , a light emitting layer etching process of etching portions 310 of the first light emitting layer 210 and the second light emitting layer 220 is performed. A portion 310 of the second light emitting layer 220 is etched at regular intervals to electrically insulate each of the fine LEDs to be generated so that they can be easily separated and diced.

A portion 320 of the first light emitting layer 210 is etched so that the N electrode can be disposed. A portion 320 of the first light emitting layer 210 is etched so that the N electrode connected to the second light emitting layer 220 can be disposed.

Referring to FIG. 4 , a reflective film 410 deposition process of depositing the reflective film 410 on top of the first light emitting layer 210 is performed. The reflective film 410 is deposited on top of the first light emitting layer to serve as a P-electrode, and at the same time reflects light emitted from the first light emitting layer 210 so that light is emitted in a certain direction (top).

The reflective film 410 may be implemented with Ni/Ag, but is not limited thereto, and any material capable of producing the above effect may be substituted.

Referring to FIG. 5 , an electrode arrangement process of disposing the N electrode 510 on the etched portion of the first light emitting layer 210 is performed. Accordingly, power may be applied to each of the light emitting layers 210 and 220 via the respective electrodes 410 and 510 .

The N electrode 510 may be implemented with Cr/Au, but is not limited thereto.

Referring to FIG. 6 (a), an insulating film deposition process of depositing an insulating film 610 is performed to separate the components to be deposited on the outside and on the top. An insulating film 610 is deposited on the previously grown or deposited components to protect the previously grown or deposited components (emission layer, electrode) from the outside and to separate them from other components to be deposited thereon.

Referring to FIG. 6( b ), a polishing process for planarizing the surface is performed so that a bonding electrode can be deposited on the deposited insulating film thereafter. The polishing process may be, for example, chemical mechanical polishing (CMP), but is not limited thereto. Since the reflective film 410 serving as the P electrode and the N electrode 510 may have a height difference, polishing together with the insulating film removes a height difference that may occur between the electrodes.

Referring to FIG. 7 , a bonding electrode deposition process of depositing a bonding electrode 710 for bonding is performed on the deposited insulating film 610 . The bonding electrode 710 deposited on the insulating film 610 is connected to the reflective film 410 and the N electrode 510, respectively. Since the area of each electrode 410 and 510 is small, the bonding electrode 710 serves to expand the area of each electrode and easily supplies power to the light emitting layers 210 and 220 using the bonding electrode 710 from the outside. play a role in supplying

The fine LED 100 is manufactured through each process shown in FIGS. 2 to 7 . Each of a plurality of fine LEDs 100 emitting the same color is fabricated on the temporary substrate 230 .

8 to 12 are diagrams illustrating a process of fabricating a TFT according to an embodiment of the present invention.

Referring to FIG. 8 , a TFT deposition process of depositing a thin film transistor (TFT) 810 on a wafer 820 is performed.

Referring to FIG. 9 , an etching process for etching the deposited TFT 810 is performed. In order to separate the TFTs to be disposed in each fine LED 100, the TFTs 810 are etched at regular intervals 910.

Referring to FIG. 10 , a deposition process of depositing a bonding electrode 1010 on the TFT 810 is performed. The bonding electrode 1010 is bonded to the bonding electrode 710 of the micro LED 100 to control the micro LED 100 .

Referring to FIG. 11 , a grinding process of grinding the wafer 820 of the TFT 810 to have a thickness suitable for being included in the fine LED package 100 is performed.

Thereafter, an electrode deposition process of depositing an electrode 1110 to be connected to the counter substrate 130, in particular, the solder 135, is performed on the opposite side of the wafer 820 on which the TFT 810 is deposited.

Referring to FIG. 12 , a bump ball deposition process is performed in which a bump ball 1210 is deposited on each bonding electrode 1010 deposited on a TFT. When the bonding electrode 1010 is bonded to the bonding electrode 710 of the micro LED 100, a bump ball 1210 is deposited on the bonding electrode 1010 to increase bonding efficiency.

13 to 16 are diagrams illustrating a process of manufacturing a micro LED package by combining a micro LED and a TFT manufactured according to an embodiment of the present invention.

Referring to FIG. 13 , a bonding process of bonding the fine LED 110 onto the TFT 120 using laser reflow is performed. In particular, the bonding electrode 710 in the micro LED 110 is bonded on the bonding electrode 1010 or the bump ball 1210 in the TFT 120 . At this time, laser reflow may be used in the bonding process. As laser reflow is used, the bonding electrode 710 in the micro LED 110 can be bonded onto the bump ball 1210 in the TFT 120 . The fine LED 110 is implemented in the form of a flip chip in which electrodes are directly connected to the TFT 120 without a separate intermediate medium.

Referring to FIG. 14 , an underfill process of underfilling a space between the fine LED 110 and the TFT 120 with an insulating material 1410 is performed. After the underfill process, the temporary substrate 230 is separated from the interface between the fine LEDs 110, particularly, the light emitting layers 210 and 220. At this time, a shock wave is generated and a large pressure is applied to the interface. The interface is separated by this pressure, and at this time, the fine LED 110, in particular, the light emitting layers 210 and 220 are greatly impacted by the shock wave. This impact also partially affects the light emitting layers 210 and 220, and has a large effect between the fine LED 110 and the TFT 120. Due to this influence, a problem in which the fine LED 110, in particular, the light emitting layers 210 and 220 may be damaged may occur. Accordingly, as the insulating material 1410 having a low viscosity characteristic is injected between the microscopic LEDs 110 and the TFT 120 and cured, the temporary substrate 230 is separated from the microscopic LEDs 110 and shock waves generated are buffered. . Additionally, as the underfill process is performed, chemical transformation that may be caused by external physical impact, heat, dust, or the like on the microscopic LEDs 110 and the TFTs 120 is prevented.

Referring to FIG. 15(a) , after the underfill process is completed, a separation process of separating the fine LEDs 110 from the temporary substrate 230 is performed. Since all processes of manufacturing the fine LEDs 110 and bonding them to the TFTs 120 have been performed, the temporary substrate 230 is separated from the fine LEDs 110 .

Referring to FIG. 15(b) , after the temporary substrate 230 is separated, a passivation process of passivating the micro LEDs 110 is performed. After the separation process is performed, one surface of the minute LEDs 110 deposited on the temporary substrate 230 is exposed to the outside. Accordingly, a passivation process is performed on one surface of the fine LED 110 from which the temporary substrate 230 is separated to prevent physical or chemical transformation or damage from occurring to the fine LED 110 . In the passivation process, a coating thin film 1510 having a low refractive index and high hardness is deposited on the micro LEDs 110 to protect the micro LEDs 110 . The deposited coating thin film 1510 may have a refractive index of 1.4 to 1.6.

Referring to FIG. 16 (a), after the passivation process is completed, a dicing process for separating into fine LED packages 100a, 100b, and 100c is performed. When the passivation is completed, the completed fine LED packages are separated into individual fine LED packages. A plurality of passivated micro LED packages are diced so that one micro LED 110 and one TFT 120 are included in each micro LED package. As described above, the fine LED 110 and the TFT 120 are formed by being etched at regular intervals and then deposited. Accordingly, each fine LED package (100a, 100b, 100c) is manufactured.

In FIG. 16( b ), a transfer process in which each of the fine LED packages 100a, 100b, and 100c is transferred to the counter substrate 130 is performed. Using laser transfer, each of the fine LED packages 100a, 100b, and 100c is transferred to a predetermined position of the counter substrate 130. In particular, it is transferred onto the solder 135 on the counter substrate 130 .

17 is a flowchart illustrating a method of producing a micro LED package according to an embodiment of the present invention.

A bonding process of bonding the fine LED 110 onto the TFT 120 using a laser is performed (S1710). Fine LEDs 110 fabricated through the fabrication process shown in FIGS. 2 to 7 are bonded onto the TFT 120 . At this time, laser reflow is used so that the fine LED 110 can be bonded onto the TFT 120 without removing the bump ball 1210 .

An underfill process of underfilling between the fine LED 110 and the TFT 120 is performed (S1720). The insulating material between the fine LED 110 and the TFT 120 is underfilled.

A separation process of separating the temporary substrate 230 on which the fine LEDs 110 are grown is performed (S1730). Since all processes of manufacturing the fine LEDs 110 and bonding them to the TFTs 120 have been performed, the temporary substrate 230 is separated from the fine LEDs 110 .

After separating each micro LED package by dicing to include one micro LED 110 and one TFT 120, a dicing process and a transfer process of transferring to the counter substrate 130 are performed (S1740).

In FIG. 17, it is described that each process is sequentially executed, but this is merely an example of the technical idea of one embodiment of the present invention. In other words, those skilled in the art to which an embodiment of the present invention pertains may change the order of the processes described in each drawing and execute one or more of the processes without departing from the essential characteristics of the embodiment of the present invention. Since various modifications and variations can be applied by executing the process in parallel, FIG. 17 is not limited to a time-series sequence.

Meanwhile, the processes shown in FIG. 17 can be implemented as computer readable codes on a computer readable recording medium. A computer-readable recording medium includes all types of recording devices in which data that can be read by a computer system is stored. That is, computer-readable recording media include magnetic storage media (eg, ROM, floppy disk, hard disk, etc.), optical reading media (eg, CD-ROM, DVD, etc.) and carrier waves (eg, Internet Transmission through) and the same storage medium. In addition, the computer-readable recording medium may be distributed to computer systems connected through a network to store and execute computer-readable codes in a distributed manner.

The above description is merely an example of the technical idea of the present embodiment, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment, but to explain, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of this embodiment should be construed according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights of this embodiment.

100: fine LED package
110: fine LED
120: TFT
130: counter substrate
135: solder
210, 220: light emitting layer
230 Temporary board
410: reflective film
510: N electrode
610: insulating film
710, 1010: bonding electrode
810: TFT
820: wafer
1110: electrode
1210: bump ball
1410: insulation material
1510: coating thin film

Claims (1)

a TFT including a bonding electrode formed on one surface by deposition, a wafer and a rear electrode disposed on the opposite side of the one surface on which the bonding electrode is disposed, and a bump disposed on the bonding electrode; and
Including a bonding electrode bonded on the bump of the TFT by laser reflow, including a micro LED forming one package with the TFT,
The fine LED emits light itself without a color filter,
The bonding electrode of the fine LED is directly connected to the bump of the TFT without an intermediate medium, and at the same time is connected to the reflective film and the N electrode serving as the P electrode of the fine LED,
Between the TFT and the fine LED is underfilled with an insulating material,
In the process of bonding the fine LED with the TFT, the substrate on which it grew is separated, and a coating thin film deposited for passivation is disposed on one side of the substrate from which the substrate is separated,
The bonded TFT and fine LED are formed by dicing into a plurality of fine LED packages each including one TFT and one fine LED,
The TFT controls the operation of each micro LED in each micro LED package,
The plurality of fine LED packages formed by bonding the fine LED and the TFT are transferred to a predetermined position on a counter substrate at regular intervals and connected to the counter substrate, and the TFT disposed at the lower end of each fine LED package is transferred to a predetermined position on the counter substrate. A fine LED package, characterized in that connected to the substrate.

Images