WO2020032394A1 - Method for manufacturing display apparatus - Google Patents

Abstract

The present invention relates to a method for manufacturing a display apparatus, and more particularly, to a method for manufacturing a display apparatus capable of quickly transferring a micrometer-sized light-emitting diode (LED) to a display panel. The method for manufacturing a display apparatus according to an embodiment comprises: a pick-up step of picking up some pixels among a plurality of pixels formed on a wafer by using a surface transfer frame having a plurality of holes; and a transfer step of transferring, onto a display panel, the some pixels picked up by the surface transfer frame.

Description

Manufacturing method of display device

The present invention relates to a method of manufacturing a display device, and more particularly, to a method of manufacturing a display device capable of quickly and efficiently transferring a light emitting diode (LED) having a micro unit size to various size display panels. .

A light emitting diode (LED) is one of light emitting devices that emit light when a current is applied. Light emitting diodes can emit high-efficiency light at low voltages, resulting in excellent energy savings. Recently, the luminance problem of the light emitting diode has been greatly improved, and has been applied to various devices such as a backlight unit, a display board, a display, and a home appliance of a liquid crystal display.

Recently, display devices using light emitting diodes have been actively developed. Most display device technologies use three light emitting diode (red, green, blue) chips to implement one pixel. However, since the driving current is different for each chip, it is difficult to configure the same driving circuit. In addition, since different types of light emitting diode chips, there is a disadvantage in that the lifetime is different.

Micro light-emitting diodes (μ-LEDs) are very small, ranging in size from 1 to 100 μm, and more than 25 million pixels are required to implement a 40-inch display device. Therefore, there is a problem in that it takes at least one month in a simple pick and place method to make a 40-inch display device.

1 is a diagram illustrating the limitation of the existing 1: 1 pick & place transfer method.

Referring to FIG. 1, a plurality of conventional micro light emitting diodes (μ-LEDs) are manufactured on a sapphire substrate, and then the micro light emitting diodes are picked and placed by pick and place, which is a mechanical transfer method. One by one, transferred to glass or a flexible substrate. Since the micro LEDs are picked up and transferred one by one, the method is called a 1: 1 pick and place transfer method.

However, since the size of the micro LED chip fabricated on the sapphire substrate is small and thin, the chip may be damaged, the transfer may fail, or the alignment of the chip may occur during the pick and place transfer process of transferring the micro LED chips one by one. Problems such as alignment fail or chip tilt occurs. In addition, there is a problem that the time required for the transfer process takes too long.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a method of manufacturing a display device capable of quickly transferring a plurality of pixels formed on a wafer to a display panel.

In addition, the present invention provides a method for manufacturing a display device that can quickly manufacture a large-area display device.

It is also possible to transfer red, green and blue micro light emitting diodes individually, but more preferably in one pixel unit comprising a plurality of light emitting diodes (eg red, green and blue light emitting diodes). Provided is a method of manufacturing a display device that can be transferred.

In addition, the present invention provides a method of manufacturing a display apparatus capable of manufacturing various types of display panels having different intervals between pixels using one surface transfer frame.

The present invention also provides a method of manufacturing a display device capable of removing a bad pixel from a plurality of pixels disposed on a wafer and reworking a new pixel.

The problem to be solved of the present invention is not limited to the above-mentioned problems, and other tasks not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

A method of manufacturing a display device according to an embodiment includes a pickup step of picking up some pixels of a plurality of pixels formed on a wafer using a surface transfer frame having a plurality of holes; And a transferring step of transferring the some pixels picked up by the surface transfer frame onto a display panel.

Here, some of the picked up pixels correspond one-to-one with the plurality of holes of the surface transfer frame, and the spacing between the plurality of holes of the surface transfer frame is greater than the spacing between the plurality of pixels formed on the wafer, The spacing between the plurality of holes of the surface transfer frame may be equal to the spacing between pixels transferred to the display panel.

Here, some of the picked-up pixels correspond one-to-one with the plurality of holes of the surface transfer frame, and the spacing between the plurality of holes of the surface transfer frame may be an integer multiple of the spacing between the plurality of pixels formed on the wafer. have.

Here, each hole of the surface transfer frame may correspond to the shape of each pixel formed on the wafer, and may have a size that can accommodate each pixel.

Here, the picking-up step may be performed by placing the surface transfer frame on a plurality of pixels formed on the wafer and using any one or a combination of vacuum, taping, magnet, and physical. The pixels may be moved to the plurality of holes in one-to-one correspondence with the holes of.

The surface transfer frame may include a micro vacuum passage formed to be connected to the plurality of holes, and the picking-up step may include placing the surface transfer frame on a plurality of pixels formed on the wafer and transferring the surface transfer. The micro vacuum passage of the frame may be vacuum suctioned to move the some pixels one-to-one corresponding to the plurality of holes of the surface transfer frame to the plurality of holes.

The surface transfer frame may include an impact absorbing layer disposed on an upper surface of the surface transfer frame and the plurality of holes; And a micro vacuum passage formed between the surface transfer frame and the shock absorbing layer and connected to the plurality of holes, wherein the pick-up step comprises: placing the surface transfer frame on a plurality of pixels formed on the wafer. Position and vacuum-suck the micro vacuum passage of the surface transfer frame to move the some pixels one-to-one corresponding to the plurality of holes of the surface transfer frame to the plurality of holes, wherein the moved some pixels contact the shock absorbing layer. You can do that.

Here, the picking-up step may include placing the surface transfer frame on a plurality of pixels formed on the wafer and using one of tape or magnets to correspond one-to-one with the plurality of holes of the surface transfer frame. Can be moved to the plurality of holes.

The method may further include repeating the pickup step and the transfer step by transferring a plurality of pixels formed on the wafer to the display panel by repeating a predetermined number of times.

Wherein the transferring step transfers the partial pixels picked up to the surface transfer frame to a first position on the display panel, and the repeating step transfers the other partial pixels picked up to the surface transfer frame onto the display panel. Can be transferred to a second position different from the first position.

Wherein the transferring step transfers the partial pixels picked up to the surface transfer frame to a first position on the display panel, and the repeating step transfers the other partial pixels picked up to the surface transfer frame onto the display panel. The second position may be transferred to a second position where the portion overlaps with the first position.

Here, the interval between the pixels transferred on the display panel may be smaller than the interval between the plurality of holes of the surface transfer frame or larger than the interval between the plurality of pixels formed on the wafer.

Wherein, before the pick-up step, a removing step of inspecting a plurality of pixels formed on the wafer and removing bad pixels; Repeating the pick-up step and the transfer step a predetermined number of times to transfer a plurality of pixels formed on the wafer to the display panel; And a rework step of filling the empty part in which no pixel is disposed on the display panel with a new pixel after the repeating step.

Wherein, between the pick-up step and the transfer step, a removing step of inspecting some pixels picked up in the surface transfer frame and removing bad pixels; An iterative step of transferring the plurality of pixels formed on the wafer to the display panel by repeating the pickup step, the removal step and the transfer step a predetermined number of times; And a rework step of filling the empty part in which no pixel is disposed on the display panel with a new pixel after the repeating step.

Here, in the removing step, the driving of some pixels picked up by the surface transfer frame may be inspected by applying a predetermined power signal to the conductive pattern formed on the surface transfer frame.

Here, before the pick-up step, the pixel forming step of forming the plurality of pixels on the wafer further comprises, wherein the pixel forming step, a first conductivity type semiconductor layer, one same wavelength of light on the wafer A plurality of active layers emitting emission and a plurality of second conductive semiconductor layers may be sequentially formed on each of the active layers, and a wavelength conversion layer may be coated on each of the second conductive semiconductor layers.

Using the method of manufacturing the display device according to the embodiment has the advantage of being able to quickly transfer a plurality of pixels formed on the wafer to the display panel.

In addition, there is an advantage that a large area display device can be manufactured quickly.

In addition, there is an advantage that can be transferred to each of the three individual red, green, and blue micro LEDs.

In addition, the color conversion process is performed on a wafer in advance in one pixel unit including a plurality of light emitting diodes (for example, red, green, and blue light emitting diodes), thereby increasing the efficiency of the process. There is an advantage to this. When the transfer process is performed in units of pixels, the same chip implements red, green, and blue, so that the same current can be easily controlled and has the same lifetime, thereby improving reliability.

In addition, there is an advantage in that a plurality of display panels having different intervals between pixels may be manufactured using one surface transfer frame.

In addition, there is an advantage in that a rework of removing a bad pixel and filling a new pixel among a plurality of pixels disposed on a wafer is possible. Therefore, the defective rate of the display panel can be significantly reduced.

1 is a view for explaining the limitation of the conventional 1: 1 pick & place (pick & place) transfer method.

2 is a flowchart illustrating a method of manufacturing a display device according to an embodiment of the present invention.

3A to 3D are process diagrams for conceptually explaining a method for manufacturing a display device according to an embodiment of the present invention shown in FIG. 2.

FIG. 4 is a perspective view of the surface transfer frame STF shown in FIG. 3B.

5 is a diagram for explaining one method of picking up the pixel 15 into the surface transfer frame.

FIG. 6A is an enlarged view of a portion A of the surface transfer frame 30 shown in FIG. 4, and FIG. 6B is a plurality of wafers formed in the wafer 10 shown in FIG. 3A. Show a portion of the pixels 15.

FIG. 7 is a diagram for explaining a transfer method different from the transfer method in FIG.

8 is a flowchart illustrating a method of manufacturing a display device according to another embodiment of the present invention.

9 is a flowchart for describing a method of manufacturing a display device according to still another embodiment of the present invention.

10A to 10B are diagrams for describing an example of the pixel 15 illustrated in FIG. 3 in detail.

In the description of the embodiments, when described as being formed on the "top" or "bottom" of each component, the top (bottom) or the bottom (bottom) is the two components are in direct contact with each other. Or one or more other components disposed between and formed between the two components. In addition, when expressed as "up (up) or down (down)" may include the meaning of the down direction as well as the up direction based on one component.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

2 is a flowchart illustrating a method of manufacturing a display device according to an embodiment of the present invention.

Referring to FIG. 2, in the method of manufacturing a display apparatus according to an exemplary embodiment of the present invention, forming a plurality of pixels 15 on a wafer 10 (S210) and using a surface transfer frame (STF) 30. Picking up some of the plurality of pixels 15 on the wafer 10 (S230), and placing the picked up pixels 15 on the display panel 50 (S250). It may include.

Here, the method may further include determining whether S210 and S230 have been repeatedly executed a predetermined number of times after the step S250 (S270). If S210 and S230 have been performed a predetermined number of times, the process ends. Otherwise, S210 and S230 are repeatedly performed.

S210, S230, S250, S270 will be described in detail with reference to the drawings below.

3A to 3D are process diagrams for conceptually explaining a method for manufacturing a display device according to an embodiment of the present invention shown in FIG. 2.

Referring to FIG. 3A, a plurality of pixels 15 are formed on the wafer 10. The plurality of pixels 15 are formed on the wafer 10 spaced apart by a predetermined interval (called 'first interval'). The first interval between the pixels 15 adjacent to each other may be constant at a predetermined interval.

One pixel 15 emits predetermined light, and the emitted light has wavelengths of various colors. For example, the light of the visible wavelength, the light of the white wavelength, the light of the ultraviolet wavelength, and the light of the infrared wavelength can be emitted. One pixel 15 may also be referred to as one 'light emitting cell'.

One pixel 15 may include at least a plurality of micro LEDs. For example, one pixel 15 may include a micro LED emitting light of a red wavelength, a micro LED emitting light of a green wavelength, and a micro LED emitting light of a blue wavelength. An example of one pixel 15 will be described later with reference to FIG. 10.

Here, one pixel 15 is not limited to including three micro LEDs. One pixel 15 may mean one micro LED. For example, one pixel 15 may be a micro LED emitting light of a red wavelength, a micro LED emitting light of a green wavelength, or a micro LED emitting light of a blue wavelength.

In addition, one pixel 15 may include two micro LEDs. For example, one pixel 15 may be composed of a micro LED emitting red light and a micro LED emitting green light, and a micro LED emitting green light and blue wavelength light. It may be composed of a micro LED emitting light, and may be composed of a micro LED emitting blue light and a micro LED emitting red light.

Referring to FIG. 3B, some pixels of the plurality of pixels 15 on the wafer 10 are picked up using the surface transfer frame 30.

As shown in FIG. 4, the surface transfer frame 30 has a plate shape and has a plurality of holes 33 penetrating the upper and lower surfaces.

The material of the surface transfer frame 30 may be steel (SUS). However, the present invention is not limited thereto, and the material of the surface transfer frame 30 may be any that can replace the sus.

In the surface transfer frame 30, a micro vacuum passage may be formed on one surface of the surface transfer frame 30. The micro vacuum passage may be connected to each hole 33. Here, the micro vacuum passage may be formed on either or both of the top and bottom surfaces of the surface transfer frame 30.

A conductive pattern may be formed on the surface transfer frame 30. The conductive pattern may be formed in the surface transfer frame 30 to provide a predetermined power source to the pixels 15 to be disposed in each hole 33.

The plurality of holes 33 are formed in the surface transfer frame 30 spaced apart by a predetermined interval (called 'second interval'). The second spacing between two adjacent holes 33 of the plurality of holes 33 may be constant.

Each hole 33 may be sized to accommodate one pixel 15 shown in FIG. 3A. That is, the holes 33 and the pixels 15 correspond to 1: 1. Therefore, the width and height of each hole 33 may be equal to or larger than the width and height of one pixel 15. The reason why the width and height of each hole 33 is larger than the width and height of one pixel 15 is that each hole 33 completely accommodates one pixel 15.

Here, since each hole 33 is sized to accommodate one pixel 15, it may not pick up the misaligned pixel or the tilted pixel shown in FIG. Since the failed alignment pixel or the tilted pixel is difficult to expect normal operation after being transferred to the display panel 50 later, the failed alignment pixel or tilted pixel may be removed by the surface transfer frame 30. There is an advantage to this.

In addition, each hole 33 may have a shape corresponding to one pixel 15. In addition, the depth of each hole 33 may be equal to or greater than the height of one pixel 15.

The surface transfer frame 30 shown in FIG. 4 is placed on the plurality of pixels 15 formed in the wafer 10 shown in FIG. 3A, and the pixels 15 are placed on the surface transfer frame 30. Pick up in various ways. Then, some pixels located directly below the plurality of holes 33 of the surface transfer frame 30 among the plurality of pixels 15 formed in the wafer 10 may include the plurality of holes 33 of the surface transfer frame 30. Can move to As such, since the surface transfer frame 30 has a plurality of holes 33, the plurality of pixels 15 can be picked up in one pick-up process.

Various methods of picking up some pixels located directly below the plurality of holes 33 of the surface transfer frame 30 among the plurality of pixels 15 formed in the wafer 10 will be described in detail.

The pixels 15 may be picked up on the surface transfer frame 30 by any one of vacuum, taping, magnets, and physical forces, or a combination thereof. As a specific example, a description will be given with reference to FIG. 5.

5A and 5B are diagrams for explaining one method of picking up the pixel 15 into the surface transfer frame.

Referring to FIGS. 5A and 5B, the surface transfer frame 30 ′ is different from the surface transfer frame 30 shown in FIG. 4.

The surface transfer frame 30 ′ shown in FIG. 5B includes the frame 31, the shock absorbing layer 35 disposed on the upper surface of the frame 31 and the plurality of holes 33, and the frame 31. And a micro vacuum passage 37 formed between the shock absorbing layer 35 and connected to the plurality of holes 33. For reference, FIG. 5A is a perspective view when the shock absorbing layer 35 of FIG. 5B is removed.

The shock absorbing layer 35 may be a film having a predetermined thickness, and may be a material capable of absorbing shock from the outside. For example, the shock absorbing layer 35 may be a film of low hardness or a polymer-based material. In addition, the shock absorbing layer 35 may be a UV film, a blue film, a polyimide film, or the like.

The micro vacuum passage 37 has a micro unit in width or depth, and may be formed on the upper surface of the frame 31 as illustrated in FIG. 5A, but is not limited thereto. The micro vacuum passage 37 may be formed on the bottom surface of the shock absorbing layer 35, or may be formed together on the top surface of the frame 31 and the bottom surface of the shock absorbing layer 35.

The pixel 15 may be picked up using the surface transfer frame 30 ′ shown in FIG. 5B. A specific pick-up method involves placing a surface transfer frame 30 'on a plurality of pixels 15 formed on the wafer 10 shown in FIG. 3, and using the micro vacuum passage 37 of the surface transfer frame 30'. ) By vacuum suction to move some pixels 15 one-to-one corresponding to the plurality of holes 33 of the surface transfer frame 30 'to the plurality of holes 33, and the moved pixels 15 are moved to the shock absorbing layer ( 35).

Since the surface transfer frame 30 ′ shown in FIG. 5B includes the shock absorbing layer 35, the impact applied to some pixels 15 by vacuum suction may be alleviated or prevented. Therefore, there is an advantage that the damage of some pixels 15 can be reduced or prevented in advance.

Meanwhile, the shock absorbing layer 35 may not be present in the surface transfer frame 30 ′ shown in FIG. 5B. In this case, the micro vacuum passage 37 may be formed on one surface of the frame 31.

Referring to FIG. 6, the relationship between the plurality of pixels 15 formed in the wafer 10 of FIG. 3A and the plurality of holes 33 formed in the surface transfer frame 30 will be described in detail. Explain.

FIG. 6A is an enlarged view of the A portion of the surface transfer frame 30 shown in FIG. 4 in detail, and FIG. 6B is a view of the wafer 10 shown in FIG. A portion of the formed plurality of pixels 15 is shown. Here, part A in FIG. 6B has the same size and shape as part A in FIG. 6A.

Referring to FIG. 6B, the plurality of pixels 15 formed on the wafer are spaced apart from each other by the first interval D1. Referring to FIG. 6A, a plurality of holes 33 formed in the surface transfer frame 30 are spaced apart from each other by a second interval D2. Here, the second interval D2 may be equal to the interval between the pixels in the display panel 50 illustrated in FIG. 3C.

The second interval D2 is greater than the first interval D1. For example, the second interval D2 may be n times the first interval D2. Here, n may be a natural number. In particular, n may be a natural number greater than two.

When the second gap D2 is larger than the first gap D1, when some pixels of the plurality of pixels 15 placed on the wafer 10 are picked up by the surface transfer frame 30, the wafer 10 may be picked up. Leaves pixels except the picked up pixels. Here, the picked up pixels are not pixels that were adjacent to each other on the wafer 10. One or more pixels are left on the wafer 10 between the picked up pixels.

Again, referring to FIG. 3C, the picked-up pixels 15 are placed on the display panel 50. The surface transfer frame 30 picking up some of the pixels 15 shown in FIG. 3B is moved to a first position g1 on the display panel 50, and the pixels picked up from the surface transfer frame 30. These are separated and disposed at the first position g1 of the display panel 50. Through this process, a plurality of pixels are disposed at the first position g1 of the display panel 50.

3 (c) is intended to be a case in which the size of the display panel 50 is larger than the surface transfer frame 30, the size of the display panel 50 may be the same as the surface transfer frame 30.

The display panel 50 is provided with a semiconductor driving circuit and a power supply device for driving the pixels, and there is a position where the pixels are placed.

The spacing between the plurality of pixels 15 disposed in the display panel 50 is designed to be equal to the spacing between the plurality of holes 33 of the surface transfer frame 30 shown in FIG. Can be.

Referring again to FIG. 3D, the processes of FIGS. 3B to 3C are repeated a predetermined number of times according to the size of the display panel 50. Specifically, the surface transfer frame 30 is moved over the plurality of pixels 15 formed in the wafer 10. At this time, the surface transfer frame 30 is moved over the wafer 10 for the second time, and the moved position is different from the first moved position. That is, the surface transfer frame 30 is moved below the plurality of holes 33 of the surface transfer frame 30 to the position on the existing pixels rather than the positions on the empty pixels on the wafer 10. Then, some other pixels are picked up by the surface transfer frame 30, and the picked up pixels are disposed at the second position g2 of the display panel 50. The second position g2 may be different from the first position g1, that is, next to the first position g1, but is not limited thereto.

On the other hand, the second position g2 may partially overlap the first position g1. It demonstrates with reference to FIG.

Referring to FIG. 7, a portion of the first position g1 and the second position g2 of the display panel 50 ′ may overlap. In addition, the third position g3 may partially overlap the first to second positions g1 and g2. In addition, the fourth position g4 may partially overlap the first to third positions g1, g2, and g3. Therefore, the pixels 15g2, 15g3, and 15g4 in the second to fourth positions g2, g3, and g4 may be disposed between the pixels 15g1 in the first position g1.

Here, the display panel 50 ′ shown in FIG. 7 is different from the display panel 50 shown in FIG. 3C. The display panel 50 shown in FIG. 3C has a second interval D2 between the transferred pixels, while the display panel 50 'shown in FIG. 7 has a gap between the transferred pixels. The third interval D3 is smaller than the second interval D2. Here, the third interval D3 may be larger than the first interval D1, which is the interval of the pixels 15 formed in the wafer 10 illustrated in FIG. 6. However, the present invention is not limited thereto, and the third interval D3 may be smaller than the first interval D1, which is an interval of the pixels 15 formed in the wafer 10 illustrated in FIG. 6.

As such, the display panel 50 ′ illustrated in FIG. 7 may be manufactured as well as the display panel 50 illustrated in FIG. 3C using the surface transfer frame 30 illustrated in FIG. 6. .

In the method of manufacturing the display device according to the embodiment of the present invention described above, the plurality of pixels 15 formed in the wafer 10 at the first interval D1 are arranged in the plurality of holes 33 at the second interval D2. By using the surface transfer frame 30 having a) can be quickly transferred to the display panel (50, 50 '). Rapid transfer does not transfer the plurality of pixels 15 on the wafer 10 one by one, but rather by using the surface transfer frame 30 to select some pixels of two or more of the plurality of pixels 15 on the wafer 10. This is possible because they are transferred to the display panels 50 and 50 'at once. In addition, it is possible to quickly manufacture a large-area display panel 50 through repeated transfer.

For example, when the pixels 15 regularly arranged at 10um intervals are formed on the wafer 10, the display panel 50 has a surface transfer frame 30 when the pixels should be configured at 100um intervals. Has the same array of holes 33 and the plurality of holes 33 at the same interval of 100 um as the display panel 50. That is, the surface transfer frame 30 and the display panel 50 have the same arrangement. The surface transfer frame 30 has holes 33 at 100 um intervals, and the wafer 10 has pixels 15 at 10 um intervals. Therefore, when the surface transfer frame 30 groups 10 pixels of the wafer 10, the surface transfer frame 30 picks up only the pixels corresponding to the first position of each group and transfers the transferred to the display panel 50. If this process is repeated 10 times, all the pixels 15 on the wafer 10 may be transferred to the display panel 50.

The surface transfer concept exemplified above is formulated as follows. If the pixels 15 on the wafer 10 are called Parray and the pixels to be arranged on the display panel 50 are called Darray, the holes 33 of the surface transfer frame 30 also have the same Darray structure as the display panel 50. to be. Therefore, the relationship of Equation 1 is as follows.

<Equation 1>

Darray = kParray, with k = integer.

That is, the interval between pixels of the display panel 50 may be an integer multiple of the interval between pixels 15 on the wafer 10. If these conditions are met, all pixels except bad pixels may be placed on the display panel 50. Here, the remaining pixels remain on the wafer 10 due to the gap between the two arrays, but the pixels picked up by the surface transfer frame 30 are transferred to the display panel.

In addition, in the method of manufacturing the display apparatus according to the embodiment of the present invention, one surface transfer frame 30 may be used to manufacture display panels 50 and 50 'having various intervals between pixels. Specifically, as shown in (c) and (d) of FIG. 3, the display panel 50 having the second interval D2 is formed by repeatedly performing the transfer using the surface transfer frame 30. As shown in FIG. 7, the display panel 50 ′ may be manufactured by repeatedly performing the transfer using the surface transfer frame 30 as shown in FIG. 7.

8 is a flowchart illustrating a method of manufacturing a display device according to another embodiment of the present invention.

In the method of manufacturing the display device according to another embodiment of the present invention, in the method of manufacturing the display device illustrated in FIG. 2, a bad pixel may be inspected, a bad pixel may be removed, and a new pixel may be placed in place of the bad pixel. .

Referring to FIG. 8, the method of manufacturing the display apparatus according to another exemplary embodiment of the present invention further includes S220 and S280 in the method of manufacturing the display apparatus illustrated in FIG. 2.

S220 is performed between S210 and S230. S220 inspects the plurality of pixels 15 formed on the wafer 10, and removes a bad pixel of the plurality of pixels 15. Here, the bad pixels include pixels that do not drive, alignment failed pixels shown in FIG. 1, tilted pixels, broken pixels, and the like. In this case, the pixel which is not driven may apply a predetermined power signal to the wafer 10 to determine whether the pixel is operating.

Inspection of the bad pixels may find a bad pixel of the plurality of pixels 15 using, for example, a camera (not shown). The removal of the bad pixels may, for example, remove the bad pixel (s) inspected among the plurality of pixels 15 formed on the wafer 10 using pick and place equipment (not shown).

In S230, some of the plurality of pixels 15 on the wafer 10 are picked up using the surface transfer frame 30, and some of the plurality of holes 33 of the surface transfer frame 30 are pixels. It may not be. This is because it is determined that the defective pixel is removed in S220.

S280 is performed after S270. S280 is a rework step, in which there is an empty part at the position where the pixel should be positioned in the display panel 50, and this part is filled with a new pixel that is normally operated by using a pick and place device (not shown). The empty part of the display panel 50 is where the pixels that have been determined to be bad pixels and removed in S220 should be located.

In the manufacturing method of the display apparatus according to another embodiment of the present invention illustrated in FIG. 8, since the defective pixel is removed from the wafer 10 and the new pixel is filled in the position where the defective pixel should be located in the display panel 50. In comparison with the manufacturing method of the display device illustrated in FIG. 2, the defect of the display panel 50 may be significantly reduced.

9 is a flowchart for describing a method of manufacturing a display device according to still another embodiment of the present invention.

According to still another aspect of the present invention, there is provided a method of manufacturing a display device, which includes inspecting bad pixels, removing bad pixels, and placing new pixels in place of bad pixels. have.

Referring to FIG. 9, the method of manufacturing the display apparatus according to still another embodiment of the present invention further includes S240 and S280 in the method of manufacturing the display apparatus illustrated in FIG. 2.

S240 is performed between S230 and S250. S240 examines the plurality of pixels 15 picked up in the surface transfer frame 30 and removes the bad one of the plurality of pixels 15. Here, the bad pixel includes a pixel not driven, a broken pixel shown in FIG. 1, and the like. Here, the non-driving pixel or the broken pixel may be applied with a predetermined power signal to the surface transfer frame 30 to determine whether the pixel is operating. If the conductive pattern is patterned in the surface transfer frame 30 in advance, a power signal may be applied to the conductive pattern to determine whether the pixel inserted into the hole 33 is operated. In addition, it is possible to determine whether the pixels that are not driven or the damaged pixels are operated by using a non-contact wireless charging method. Using the non-contacting wireless charging method, there is an advantage that no separate wiring is required for the surface transfer frame 30, and it is possible to determine whether the pixel is operated even when the surface transfer frame 30 is not only fixed but also moved.

In addition, inspection of the bad pixel may find a bad pixel among the plurality of pixels 15 picked up by the surface transfer frame 30 using, for example, a camera (not shown). Removal of the bad pixels may use, for example, equipment (not shown) to pick and place the bad pixel (s) inspected among the plurality of pixels 15 picked up in the surface transfer frame 30. In addition, the amount of vacuum applied to the surface transfer frame 30 may be controlled to remove defective pixels.

S280 is performed after S270. S280 is a rework step, in which there is an empty part at the position where the pixel should be positioned in the display panel 50, and this part is filled with a new normally operated pixel by using a pick and place device (not shown). The empty portion of the display panel 50 is where pixels that have been determined to be bad pixels and removed have been located in S240.

In the method of manufacturing the display device according to still another embodiment of the present invention illustrated in FIG. 9, a new pixel is removed from the surface transfer frame 30 and a new pixel is positioned in the display panel 50. Since the gap is filled, there is an advantage that the defect of the display panel 50 can be significantly reduced as compared with the manufacturing method of the display device shown in FIG. In addition, compared to the manufacturing method illustrated in FIG. 8, since the defective pixels are inspected and removed from the surface transfer frame 30 rather than the wafer 10, inspection time is further reduced than when the defective pixels are inspected from the wafer 10. There is an advantage to this.

FIG. 10 is a diagram for describing an example of the pixel 15 illustrated in FIG. 3 in detail.

FIG. 10A is a plan view from above of the active region 15a of the pixel 15 shown in FIG. 3, and FIG. 10B is a view of the active region 15a shown in FIG. It is a cross section.

Referring to FIG. 10A, the planar structure of one pixel 15 includes the active region 15a.

The active region 15a may include a plurality of emission regions 15a1, 15a2, and 15a3. Predetermined light may be emitted from each of the plurality of light emitting regions 15a1, 15a2, and 15a3. The light emitted from the plurality of emission regions 15a1, 15a2, and 15a3 may have different wavelengths. For example, the active region 15a may include a first emission region 15a1 in which light of a red wavelength is emitted, a second emission region 15a2 in which light of a green wavelength is emitted, and a third emission in which light of a blue wavelength is emitted. Region 15a3 may be included. As another example, the active region 15a may include a light emitting region in which four different lights are emitted. The active region 15a includes a first emission region in which light of a red wavelength is emitted, a second emission region in which light of a green wavelength is emitted, a third emission region in which light of a blue wavelength is emitted, and an agent in which light of a white wavelength is emitted. It may include four emission areas. As another example, the active region 15a may include five or more light emitting regions.

The plurality of light emitting regions 15a1, 15a2, and 15a3 included in the active region 15a may be arranged in a predetermined matrix (eg, 3 * 1 and 2 * 2). The size of each light emitting region 15a1, 15a2, and 15a3 may correspond to the size of the micro light emitting diode. For example, the size of each emission region may be 3 to 200 μm.

Referring to FIG. 10D, the stacked structure of the active region 15a of the pixel 15 is mutually formed on one plane on the first conductive semiconductor layer 601 and the first conductive semiconductor layer 601. A plurality of active layers 602a, 602b, 602c spaced apart and emitting light of a particular wavelength, second conductive semiconductor layers 603a, 603b, 603c disposed on each of the active layers 602a, 602b, 603c, and respectively And a plurality of wavelength conversion layers 604a, 604b, and 604c disposed on the second conductive semiconductor layers 603a, 603b, and 603c. The number of active layers 602a, 602b, and 602c may correspond to the number of light emitting regions 15a1, 15a2, and 15a3 included in the active region 15a illustrated in FIG. 10A. . Also, the number of the plurality of second conductivity type semiconductor layers 603a, 603b, and 603c is also the number of the plurality of light emitting regions 15a1, 15a2, and 15a3 included in the active region 15a shown in FIG. 10A. May correspond to

The first conductivity type semiconductor layer 601 may be disposed on the top surface of the wafer 10 shown in FIG. 3A.

The first conductivity type semiconductor layer 601 is different from the plurality of active layers 602a, 602b and 602c, the second conductivity type semiconductor layers 603a, 603b and 603c and the plurality of wavelength conversion layers 604a, 604b and 604c. It consists of one. The first conductivity type semiconductor layer 601 may be a common layer. However, the present invention is not limited thereto, and in some cases, the first conductivity type semiconductor layer 601 may be two or more, and may be smaller than the number of the active layer and / or the second conductivity type semiconductor layer.

A first conductive type semiconductor layer 601 is formed by _{Al x In y Ga 1 -x- y} N (0 = x, y, x + y≤ = 1) of the n-type, the nitride semiconductor doped with an n-type impurity It may be made of. For example, impurities such as Si, Ge, Se, Te, or C are doped into a nitride semiconductor such as GaN, AlGaN, InGaN. The first conductivity type semiconductor layer 601 may be arranged in a single layer or multiple layers.

Although not illustrated in a separate drawing, the first conductivity-type semiconductor layer 601 may further include a current spreading layer or an ohmic layer. The current spreading layer may serve to diffuse current injected through the electrode, and the ohmic layer may serve to facilitate ohmic contact with the electrode.

The plurality of active layers 602a, 602b, and 602c are disposed on the first conductive semiconductor layer 601 and are spaced apart from the adjacent active layers by a predetermined distance. Second conductive semiconductor layers 603a, 603b, and 603c are disposed on each of the plurality of active layers 602a, 602b, and 602c. The plurality of second conductivity type semiconductor layers 603a, 603b, and 603c are spaced apart from the second conductivity type semiconductor layer adjacent to each other by a predetermined distance.

The plurality of active layers 602a, 602b, 602c are disposed apart from one another, but may have the same material and structure. Thus, the specific wavelengths of light emitted from the plurality of active layers 602a, 602b, 602c may be the same. For example, light of a blue wavelength may be emitted from the plurality of active layers 602a, 602b, and 602c. However, the present invention is not limited thereto, and the active layers 602a, 602b, and 602c may emit light of green wavelength, red wavelength, white wavelength, and ultraviolet wavelength.

Each active layer 602a, 602b, or 602c has electrons (or holes) injected through the first conductive semiconductor layer 601 and holes (or electrons) injected through the second conductive semiconductor layers 603a, 603b, and 603c. ) Meet each other and emit light due to a band gap difference depending on the material of the active layers 602a, 602b, and 602c.

Each active layer 602a, 602b, or 602c has a single well, a single quantum well, a multiple well, a multi quantum well structure (MQW), a quantum-wire structure, or a quantum dot structure. It may be formed of at least one.

Each active layer 602a, 602b, and 602c may be implemented with a compound semiconductor. The active layers 602a, 602b, and 602c may be implemented by at least one of Group II-VI and Group III-V compound semiconductors, for example.

Each of the active layers 602a, 602b, and 602c includes a plurality of well layers and a plurality of barrier layers alternately arranged, and a pair of well layers / barrier layers may be formed in 2 to 30 cycles. The period of the well layer / barrier layer is, for example, AlInGaP / AlInGaP, InGaN / GaN, GaN / AlGaN, AlGaN / AlGaN, InGaN / AlGaN, InGaN / InGaN, AlGaAs / GaAs, InGaAs / GaAs, InGaP / GaP, AlInGaP / At least one of InGaP or InP / GaAs pairs. The well layer may be disposed of a semiconductor material having a composition formula of In _x Al _y Ga _1-xy P (0 <x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y <1). The barrier layer may be formed of a semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} P (0≤x≤1, 0≤y≤1, 0≤x + y <1).

Second conductive semiconductor layers 603a, 603b, and 603c may be disposed on each of the plurality of active layers 602a, 602b, and 602c. The second conductive semiconductor layers 603a, 603b, and 603c are composed of a plurality. One second conductivity type semiconductor layer 603a may be disposed on one active layer 602a. Each of the second conductivity type semiconductor layers 603a, 603b, and 603c may be disposed on an upper surface of each of the active layers 602a, 602b, and 602c, and may be spaced apart from each other by a predetermined distance, like the plurality of active layers 602a, 602b, and 602c. .

Is formed in each of the second conductivity type semiconductor layer (603a, 603b, 603c) is a p-type _{Al x In y Ga 1 -x- y} N (0 = x, y, x + y≤ = 1), a p-type impurity It may be made of a doped semiconductor material. For example, an impurity such as Mg, Zn or Be is doped into a nitride semiconductor such as GaN, AlGaN, InGaN.

Each second conductive semiconductor layer 603a, 603b, or 603c may be arranged in a single layer or multiple layers. The second conductive semiconductor layers 603a, 603b, and 603c may be formed in a superlattice structure in which at least two different layers are alternately arranged.

Although not illustrated in a separate drawing, the second conductivity-type semiconductor layers 603a, 603b, and 603c may further include a current spreading layer or an ohmic layer. The current spreading layer may serve to diffuse current injected through the electrode, and the ohmic layer may serve to facilitate ohmic contact with the electrode.

The wavelength conversion layers 604a, 604b, and 604c are disposed on the plurality of second conductivity type semiconductor layers 603a, 603b, and 603c, respectively. The plurality of wavelength conversion layers 604a, 604b, and 604c may emit light of different wavelengths. For example, the first wavelength conversion layer 604a may emit light of red wavelength, the second wavelength conversion layer 604b may emit light of green wavelength, and the third wavelength conversion layer 604c. Can emit light of a blue wavelength. The upper surface of the first wavelength conversion layer 604a becomes the light emitting region 15a1 emitting red light, and the upper surface of the second wavelength conversion layer 604b becomes the light emitting region 15a2 emitting green light, and the third wavelength conversion The top surface of the layer 604c may be a light emitting region 15a3 emitting red light.

In this case, when the wavelength of the light that is to be emitted from the third wavelength conversion layer 604c is the same as the wavelength of the light that is emitted from the third active layer 602c, the third wavelength conversion layer 604c may be disposed on the second conductivity-type semiconductor layer 603c. This may not be arranged.

The plurality of wavelength conversion layers 604a, 604b, and 604c may include a quantum dot phosphor or a YAG phosphor. The quantum dot phosphor may include a red quantum dot phosphor that emits light of a red wavelength, a green quantum dot phosphor that emits light of a green wavelength, and a blue quantum dot phosphor that emits light of a blue wavelength. The quantum dot phosphors included in each of the wavelength conversion layers 604a, 604b, and 604c may be determined according to wavelengths of light emitted from the emission region. The same applies to yag phosphors.

As shown in FIG. 10, the pixel 15 shown in FIG. 3 includes a first conductive semiconductor layer 601 on the wafer 10, a plurality of active layers 602a and 602b that emit light of the same wavelength. , 602c), and a plurality of second conductivity type semiconductor layers 603a, 603b, and 603c are sequentially formed on each of the active layers 602a, 602b, and 602c, and each of the second conductivity type semiconductor layers 603a, 603b, and 603c. By using a color conversion process to selectively coat the wavelength conversion layer (604a, 604b, 604c) on the can be formed one pixel (15) having all the red, green, blue micro LED.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be interpreted that the contents related to such a combination and modification are included in the scope of the present invention.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Those skilled in the art to which the present invention pertains should be provided within the scope not departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are not possible. For example, each component specifically shown in embodiment can be modified and implemented. And differences relating to these modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

[Description of the code]

10: wafer

15: pixels

30: surface transfer frame (STF)

33: hall

50, 50 ': display panel

Claims (16)

A pickup step of picking up some of the plurality of pixels formed on the wafer using a surface transfer frame having a plurality of holes; And Transferring the partial pixels picked up by the surface transfer frame onto a display panel; A manufacturing method of a display device, including. The method of claim 1, The picked up pixels correspond one-to-one with a plurality of holes in the surface transfer frame, The spacing between the plurality of holes of the surface transfer frame is greater than the spacing between the plurality of pixels formed on the wafer, The spacing between the plurality of holes of the surface transfer frame is the same as the spacing between pixels transferred to the display panel. The method of claim 1, The picked up pixels correspond one-to-one with a plurality of holes in the surface transfer frame, And the interval between the plurality of holes of the surface transfer frame is an integer multiple of the interval between the plurality of pixels formed on the wafer. The method of claim 1, Each hole of the surface transfer frame corresponds to the shape of each pixel formed on the wafer and has a size that can accommodate the respective pixels. The method of claim 1, The surface transfer frame includes a micro vacuum passage formed to connect with the plurality of holes, The pick-up step may include placing the surface transfer frame on a plurality of pixels formed on the wafer and vacuum sucking a micro vacuum passage of the surface transfer frame to one-to-one correspondence with a plurality of holes of the surface transfer frame. Moving pixels to the plurality of holes. The method of claim 1, The surface transfer frame may include: an impact absorbing layer disposed on an upper surface of the surface transfer frame and the plurality of holes; And a micro vacuum passage formed between the surface transfer frame and the shock absorbing layer and connected to the plurality of holes. The pick-up step may include placing the surface transfer frame on a plurality of pixels formed on the wafer and vacuum sucking a micro vacuum passage of the surface transfer frame to one-to-one correspondence with a plurality of holes of the surface transfer frame. Moving pixels to the plurality of holes and causing the some pixels to be moved to contact the shock absorbing layer. The method of claim 1, The picking-up step includes positioning the surface transfer frame on a plurality of pixels formed on the wafer and using one of taping or magnets to select the partial pixels one-to-one corresponding to the plurality of holes of the surface transfer frame. A method of manufacturing a display device, which moves to a plurality of holes. The method of claim 1, And repeating the pick-up step and the transfer step by transferring a plurality of pixels formed on the wafer to the display panel by repeating a predetermined number of times. The method of claim 8, The transferring step may include transferring the some pixels picked up to the surface transfer frame to a first position on the display panel, And the repeating step transfers some other pixels picked up to the surface transfer frame to a second position different from the first position on the display panel. The method of claim 8, The transferring step may include transferring the some pixels picked up to the surface transfer frame to a first position on the display panel, And the repeating step transfers some other pixels picked up to the surface transfer frame to a second position where a portion overlaps with the first position on the display panel. The method of claim 10, Wherein the spacing between the pixels transferred on the display panel is less than the spacing between the plurality of holes of the surface transfer frame or greater than the spacing between the plurality of pixels formed on the wafer. The method of claim 1, A removal step of inspecting a plurality of pixels formed on the wafer and removing bad pixels before the pick-up step; Repeating the pick-up step and the transfer step a predetermined number of times to transfer a plurality of pixels formed on the wafer to the display panel; And After the repetition step, a rework step of filling a blank portion in which no pixel is disposed on the display panel with new pixels; A manufacturing method of a display device, including. The method of claim 1, A removal step of inspecting some pixels picked up in the surface transfer frame and removing bad pixels between the pickup step and the transfer step; An iterative step of transferring the plurality of pixels formed on the wafer to the display panel by repeating the pickup step, the removal step and the transfer step a predetermined number of times; And After the repetition step, a rework step of filling a blank portion in which no pixel is disposed on the display panel with new pixels; A manufacturing method of a display device, including. The method of claim 13, The removing may include applying a predetermined power signal to a conductive pattern formed on the surface transfer frame to test driving of some pixels picked up on the surface transfer frame. The method of claim 13, In the removing step, the driving of some of the pixels picked up in the surface transfer frame using a non-contact wireless charging method, the manufacturing method of the display device. The method of claim 1, Before forming the pixel, the pixel forming step of forming the plurality of pixels on the wafer; The pixel forming step may include sequentially forming a first conductive semiconductor layer on the wafer, a plurality of active layers emitting light of the same wavelength, and a plurality of second conductive semiconductor layers on each active layer, Coating a wavelength conversion layer on each said 2nd conductivity type semiconductor layer.

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