KR102173094B1 - Method for manufacturing display apparatus and display apparatus - Google Patents

Abstract

The present invention relates to a method of manufacturing display device and a display device, and more particularly, to a method of manufacturing display device and a display device manufactured thereby, capable of rapidly and efficiently transferring a plurality of RGB pixels formed on a wafer to a display panel. According to an embodiment, the method of manufacturing the display device includes: a multiple RGB pixel forming step of forming a plurality of RGB pixels on a wafer; a dicing step of dicing the wafer on which the RGB pixels are formed for each of the RGB pixels; a pixel CSP array forming step of forming a pixel CSP array in a transfer frame by placing one of the RGB pixels, which are obtained by the dicing, for each of a plurality of openings arranged in an array form on the transfer frame, and encapsulating each of the RGB pixels; a primary transfer step of adhering a carrier substrate to the pixel CSP array and the transfer frame, and transferring the pixel CSP array from the transfer frame to the carrier substrate by using a difference between first adhesive strength between the pixel CSP array and the transfer frame and second adhesive strength between the pixel CSP array and the carrier substrate, in which the second adhesive strength is greater than the first adhesive strength; and a secondary transfer step of transferring the pixel CSP array transferred to the carrier substrate to a display panel.

Description

A display device manufacturing method and a display device TECHNICAL FIELD [METHOD FOR MANUFACTURING DISPLAY APPARATUS AND DISPLAY APPARATUS}

The present invention relates to a method of manufacturing a display device and a display device, and more particularly, a method of manufacturing a display device capable of quickly and efficiently transferring a plurality of RGB pixels formed from a wafer to a display panel, and a display device manufactured thereby. It is about.

Light Emitting Diode (LED) is one of light emitting devices that emit light when current is applied. Light-emitting diodes can emit high-efficiency light with low voltage, so they have excellent energy saving effects. Recently, the problem of luminance of light emitting diodes has been greatly improved, and thus, it has been applied to various devices such as backlight units of liquid crystal display devices, electric signs, displays, and home appliances.

The size of a micro light emitting diode (μ-LED) is very small, ranging from 1 to 100 μm, and approximately 25 million or more pixels are required to implement a 40-inch display device. Accordingly, there is a problem in that it takes at least one month in time by a simple pick and place method to make one 40-inch display device. Existing micro light-emitting diodes (μ-LEDs) are manufactured in plural on a sapphire substrate, and then, by a mechanical transfer method, pick & place, the micro light-emitting diodes are one by one on a glass or flexible substrate. Is transferred. Since the micro light emitting diodes are picked up one by one and transferred, it is referred to as a 1:1 pick-and-place transfer method. However, since the size of the micro light emitting diode chip manufactured on the sapphire substrate is small and thin, the chip is damaged, the transfer fails, or the chip is aligned during the pick-and-place transfer process of transferring the micro light emitting diode chips one by one. Problems such as (Alignment) failure or chip tilting occur. In addition, there is a problem that the time required for the transfer process takes too long.

There is a mini light emitting diode (Mini-LED) that is distinguished from micro light emitting diodes. Mini LED refers to a product that has an LED chip size of 100 to 200 micrometers (㎛). The chip size is slightly larger than the micro LED, but like the micro LED, each chip can be used as a pixel or a light emitter. The advantage of mini LED is that the production cost is lower than that of micro LED, and a large part of the existing LED production process can be utilized. Recently, investment and development in mini LEDs are underway because it is determined that it may take a longer time than expected to commercialize a highly technically difficult micro LED, but since the conventional general pick and place transfer process is still used, the transfer described above. During the process, the chip is damaged, the transfer fails, the alignment of the chip fails, the tilt of the chip occurs, or the transfer process takes too long a problem.

The present invention provides a method of manufacturing a display device capable of rapidly transferring a plurality of RGB pixels to a display panel.

In addition, a method of manufacturing a display device capable of rapidly manufacturing a mini LED-based display device and minimizing a transfer error is provided.

In addition, it provides a method of manufacturing a display device capable of rapidly manufacturing a micro LED-based display device and minimizing transfer errors.

In addition, a method of manufacturing a display device capable of rapidly manufacturing a large-area display device is provided.

In addition, there is provided a display device manufactured by a method of manufacturing a display device.

The problem to be solved of the present invention is not limited to the problems mentioned above, and other problems that are not mentioned can be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. will be.

A method of manufacturing a display device according to an embodiment includes the steps of forming a plurality of RGB pixels on a wafer, forming a plurality of RGB pixels; Dicing the wafer on which the plurality of RGB pixels are formed for each of the RGB pixels; Forming a pixel CSP array in the transfer frame by disposing one diced RGB pixel for each of a plurality of openings arranged in an array form in a transfer frame and encapsulating each of the RGB pixels to form a pixel CSP array in the transfer frame; A carrier substrate is adhered to the pixel CSP array and the transfer frame, and a first adhesion force between the pixel CSP array and the transfer frame, and a second adhesion force between the pixel CSP array and the carrier substrate greater than the first adhesion force A primary transfer step of transferring the pixel CSP array from the transfer frame to the carrier substrate by using the difference of; And a secondary transfer step of transferring the pixel CSP array transferred to the carrier substrate to the display panel.

The display device according to the embodiment may be manufactured by the method of manufacturing the display device described above.

The use of the method of manufacturing a display device according to the embodiment has an advantage in that a plurality of RGB pixels can be quickly and efficiently transferred to a display panel by directly arranging RGB pixels in the form of a single chip on a wafer as a transfer frame. .

In addition, in the method of manufacturing a display device according to the embodiment, a plurality of light emitting devices can be quickly transferred to the display panel without controlling each of the micro- or mini-class light-emitting devices. Therefore, there is an advantage in that manufacturing cost and time of the display device can be significantly reduced.

In addition, the method of manufacturing the display device according to the embodiment has an advantage of maximizing a transfer success rate because it uses a large difference in adhesion between transfer media, not a method of controlling physical force or adhesion such as electrostatic attraction.

In addition, when the size of the light emitting area of the light emitting device is 100 μm or less, the light efficiency rapidly decreases due to epi damage caused by dicing or the like. On the other hand, the present invention has an advantage that the light efficiency does not deteriorate because the transfer is performed in a pixel CSP unit rather than a light emitting diode chip unit. More specifically, when the dicing process is performed, damage may be caused by the laser. The percentage (%) occupied by the damaged portion of the light emitting area varies according to the size of the light emitting area Epi of the light emitting diode. That is, the ratio of the length of the surface circumference to the area increases as the size of the light emitting area decreases. For example, when the size of the light emitting area is 300x300um, the surface-to-area ratio is 1, and 50x50um is about 6 times larger. Therefore, the influence of defects on the surface can be at least 6 times greater. As a result, the luminous efficiency drops sharply. On the other hand, the present invention is not dicing in units of chips, but dicing in units of pixels, regardless of the EPI area. Therefore, there is an advantage that there is little reduction in light efficiency at the pixel level.

In addition, when manufacturing a large-area display device, there is an advantage in that the transfer method can be rapidly manufactured by changing the position and repeatedly executing the transfer method.

1 is a flowchart illustrating a method of manufacturing a display device according to an embodiment of the present invention.
2A to 2B are diagrams for explaining an embodiment of step 110 shown in FIG. 1.
3 to 6 are diagrams for explaining an embodiment of steps 110 and 130 shown in FIG. 1.
7A to 7C are diagrams for explaining a transfer frame 200 used in a method of manufacturing a display device according to an embodiment of the present invention shown in FIG. 1.
8 to 12 are diagrams for explaining in detail the step 150 of forming a pixel CSP array in the transfer frame shown in FIG. 1.
13 to 16 are diagrams for explaining in detail a step of expanding a pad in each pixel CSP in a pixel CSP array formed in a transfer frame.
18 to 20 are diagrams for explaining in detail a step 170 of transferring the pixel CSP array formed on the transfer frame shown in FIG. 1 to a carrier substrate.
21 to 25 are diagrams for explaining in detail a step 190 of transferring the pixel CSP array transferred to the carrier substrate shown in FIG. 1 to the display panel.
26 is a view showing a comparison before and after movement of an electrode pad of a display panel.
FIG. 27 is a diagram for describing in detail a step of transferring a pixel CSP array having expansion pads transferred to a carrier substrate to a display panel.

In the description of the embodiment, in the case of being described as being formed on the “top (top) or bottom (bottom)” of each component, the top (top) or bottom (bottom) of the two components directly contact each other Or one or more other components are disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

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

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

Referring to FIG. 1, a method of manufacturing a display device according to an embodiment of the present invention includes forming a plurality of RGB pixels on a wafer (110), dicing a wafer for each RGB pixel (130), and transferring Step 150 of forming a pixel CSP array on the frame, transferring the pixel CSP array formed on the transfer frame to a carrier substrate 170, and transferring the pixel CSP array transferred to the carrier substrate to the display panel. Step 190 is included. Steps 110, 130, 150, 170, and 190 will be described in detail below with reference to the accompanying drawings.

2A to 2B are diagrams for explaining an embodiment of step 110 shown in FIG. 1.

Referring to FIG. 2A, a plurality of light-emitting elements 11 that emit light of the same wavelength band are formed on one wafer 10. Here, the light emitting device 11 may be a light emitting chip that emits blue light, but is not limited thereto, and the light emitting device 11 may be a light emitting chip that emits red light or a light emitting chip that emits green light. It may be a light emitting chip that emits white light, or a light emitting chip that emits ultraviolet light.

The plurality of light emitting devices 11 may be arranged along a plurality of rows and columns on the wafer 10. Here, at least three of the plurality of light emitting devices 11 may constitute one group. The size (horizontal*vertical) of one group may correspond to the size (horizontal*vertical) of one pixel.

Next, referring to FIG. 2(b), color conversion layers 15R and 15G on some of the plurality of light-emitting elements 11 on one wafer 10 formed in FIG. 2(a) To form. For example, a first color conversion layer 15R is formed on the leftmost light emitting device in each of a plurality of groups constituting the plurality of light emitting devices 11, and the light emitting device located in the middle of each of the plurality of groups. A second color conversion layer 15G may be formed. Here, the first color conversion layer 15R may be a red conversion layer that emits red light in response to blue light, and the second color conversion layer 15G may be a green conversion layer that emits green light in response to blue light.

By forming the color conversion layers 15R and 15G on some light emitting devices, a plurality of RGB pixels 100 may be formed on one wafer 10 as shown in FIG. 2B. Each of the plurality of RGB pixels 100 formed on one wafer 10 has the advantage of being able to emit various colors, and the plurality of light-emitting elements 11 are formed by epi-growth of the same material at the same time. Since the lifetime of the pixel 100 is almost constant and the driving current is almost the same, the control method has the same advantage.

Meanwhile, after forming a plurality of RGB pixels 100 on one wafer 10, the wafer 10 may be diced for each RGB pixel 100 to separate each RGB pixel 100.

3 to 6 are diagrams for explaining an embodiment of steps 110 and 130 shown in FIG. 1.

Referring to FIG. 3, an epitaxial 11' emitting a predetermined light is grown on one surface of a wafer 10'. Here, the wafer 10 ′ may be a sapphire (Al2O3) substrate. A pad 17 is formed on the grown epitaxial 11', and a protective layer 13 for passivating the epit 11' and the pad 17 is formed. When forming the protective layer 13, it is preferable to form the pad 17 to be exposed to the outside of the protective layer 13.

Referring to FIG. 4, a blocking dam 20 is formed on the other side of the wafer 10 ′, but the blocking dam 20 is not formed on the epi 11 ′. Accordingly, an opening 20h through which a color conversion layer may be formed may be formed in the blocking dam 20. The number of openings 20h may correspond to the number of epis 11.

Referring to FIG. 5, color conversion layers 15R' and 15G' are formed in at least some of the plurality of openings 20h formed in the blocking dam 20. The color conversion layers 15R' and 15G' may include a red conversion layer 15R' and a green conversion layer 15G'. When the light emitted from the epitaxial 11' emits light in the blue wavelength band, the red conversion layer 15R' reacts to the light in the blue wavelength band emitted from the epitaxial 11' to generate light in the red wavelength band. Can be released. The green conversion layer 15G' may emit light of a green wavelength band in response to light of a blue wavelength band emitted from the epitaxial 11'.

A color conversion layer may not be formed in some of the plurality of openings 20h formed in the blocking dam 20. This is to use the light emitted from the epi (11') as it is. Of course, when the wavelength band of light emitted from the epitaxial 11 ′ is not light of the desired wavelength band, a predetermined color conversion layer may be formed in the partial openings. For example, when the epitaxial 11' emits ultraviolet light, a red conversion layer, a green conversion layer, and a blue conversion layer may be disposed in all openings.

Referring to FIG. 6, as shown in FIGS. 3 to 5, the epitaxial 11' and the color conversion layers 15R' and 15G' are formed on a wafer 10' for each RGB pixel 100'. Dicing to form a plurality of RGB pixels 100'.

7A to 7C are views for explaining the transfer frame 200 used in the manufacturing method of the display device according to the embodiment of the present invention shown in FIG. 1, and FIG. 7A is It is a perspective view of the transfer frame 200, FIG. 7(b) is a partially enlarged plan view in FIG. 7(a), and FIG. 7(c) is a cross-sectional view of FIG. 7(b).

7A to 7C, the transfer frame 200 has a plate shape, and includes an upper surface and a lower surface, and a plurality of side surfaces. The transfer frame 200 may have a flat plate shape, but is not limited thereto, and may have a plate shape having a predetermined curvature. When the transfer frame 200 has a flat plate shape, the transfer frame 200 may be referred to as a horizontal frame.

The transfer frame 200 has a plurality of openings 210. Each of the openings 210 is formed to penetrate the upper and lower surfaces of the transfer frame 200, and the plurality of openings 210 may be arranged in an array form in the transfer frame 200 in a plurality of row and column directions. The spacing (or pitch) between the plurality of openings 210 may be the same as the spacing (or pitch) of a pixel CSP array to be transferred onto a display panel to be described later.

The size of the opening 210 of the transfer frame 200 may correspond to the size of a pixel CSP (CSP). For example, the width (W) * length (h) * thickness (t) of the opening 210 of the transfer frame 200 may be 30 * 30 * 10 (μm) ~ 1000 * 1000 * 500 (μm). .

The upper opening and the lower opening of the opening 210 of the transfer frame 200 may have a rectangular shape, but are not limited thereto and may be a circle, an ellipse, or a polygon. In addition, the shapes of the upper opening and the lower opening may be different, and the sizes may be different from each other.

The three-dimensional structure of the opening 210 of the transfer frame 200 may be a hexahedral empty space, but is not limited thereto, and the shape of the opening 210 may be a cylindrical empty space or an oval-cylindrical empty space. It may be a space, a polygonal cylindrical empty space, or a polyhedral empty space.

The material of the transfer frame 200 is a hard material, and may be, for example, any one of metal, ceramic, resin, plastic, or a combination thereof.

The thickness t of the transfer frame 200 may be 10 (μm) to 500 (μm).

8 to 12 are diagrams for explaining in detail the step 150 of forming a pixel CSP array in the transfer frame shown in FIG. 1.

8 is a schematic cross-sectional view of any one of the plurality of openings 210 of the transfer frame 200 shown in FIG. 7.

Referring to FIG. 8, a substrate 300 is formed on one of the upper and lower surfaces of the transfer frame 200 (lower surface in FIG. 3 ). As the substrate 300 is formed under the transfer frame 200, the lower opening of the opening 210 is blocked by the substrate 300. A space in which a pixel CSP can be formed is provided by the opening 210 and the substrate 300.

Next, referring to FIG. 9, one RGB pixel 100 ′ is disposed on the substrate 300 inside the opening 210. In the drawings below, one RGB pixel 100 ′ is illustrated as the RGB pixel 100 ′ formed in FIG. 6, but is not limited thereto, and may be one RGB pixel 100 diced in FIG. 2. . A plurality of pads 17 of one RGB pixel 100 ′ may be disposed to contact the upper surface of the substrate 300.

One RGB pixel 100' may have a flip chip structure that does not require a wire. One RGB pixel 100' may emit light of various colors according to an external control signal.

In addition, one RGB pixel 100 ′ may be a Chip Scale Package (CSP). CSP (Chip Scale Package) is a generic term for a small package close to the size of a chip, and is a package having a size close to a bare chip without a lead frame protecting the outer shape of the chip and a wire for electrical connection.

One RGB pixel 100 ′ disposed inside the opening 210 may be included in one pixel CSP. One pixel CSP may function as one pixel that emits various colors in a display panel to be described later.

Next, referring to FIG. 10, the protective layer 500 is filled in the opening 210 and the protective layer 500 is cured. One pixel CSP 400 may include one RGB pixel 100 ′ and a passivation layer 500.

The shape of the cured protective layer 500 or the shape of one pixel CSP 400 corresponds to the shape of the opening 210 of the transfer frame 200. Accordingly, the shape of the protective layer 500 or the shape of one pixel CSP 400 may vary depending on the shape of the opening 210 of the transfer frame 200. The shape of the opening 210 of the transfer frame 200 can be understood from the shape of the protective layer 500 or the shape of one pixel CSP 400, and through this, a method of manufacturing a display device according to an embodiment of the present invention can be described. Can be estimated.

Next, referring to FIG. 11, when the protective layer 500 is cured, the substrate 300 is separated from the transfer frame 200, one RGB pixel 100 ′, and the protective layer 500. When the substrate 300 is separated, a plurality of pads 17 of the pixel CSP 400 may be exposed to the outside. The plurality of pads 17 may vary depending on the number of light emitting units included in one RGB pixel 100'. For example, if the number of light emitting units included in one RGB pixel 100' is three, Since two pads are required for each light emitting part, a total of six pads may be formed, or if the (+) electrode is a common electrode, a total of four pads may be formed.

After forming the pixel CSP 400 in each of the plurality of openings 210 of the transfer frame 200, and filling and curing the protective layer 500 for each of the plurality of openings 210, the substrate as shown in FIG. When 300 is removed from the transfer frame 200, the RGB pixels 100', and the protective layer 500, as shown in FIG. 12, a plurality of pixels are formed in the plurality of openings 210 of the transfer frame 200. A pixel CSP array including the CSP 400 may be formed.

Meanwhile, the transfer frame 200 may be referred to as a first transfer medium in a method of manufacturing a display device according to an embodiment of the present invention. More specifically, a pixel CSP array may be formed by forming a plurality of pixel CSPs including a plurality of light emitting elements on the first transfer medium. Here, each of the plurality of pixel CSPs is separated by a protective layer, and has a first adhesive force between the first transfer medium and the protective layer.

Referring back to FIG. 1, the method of manufacturing a display device according to an embodiment of the present invention may further include expanding a pad in each pixel CSP in a pixel CSP array formed in a transfer frame. This will be described with reference to FIGS. 13 to 17.

13 to 16 are diagrams for explaining in detail a step of expanding a pad in each pixel CSP in a pixel CSP array formed in a transfer frame.

Referring to FIG. 13, in a state in which the pads 17R, 17G, and 17B are exposed as shown in FIG. 11 based on one pixel CSP 400, the protective film 600 is formed on the opposite side of the pads 17R, 17G, and 17B. ) To form.

The protective film 600 is disposed on the opposite side of the pad 17 of the transfer frame 200 shown in FIG. 12, and may be attached to protect the pixel CSP during a metal deposition process using a shadow mask.

The protective film 600 is made of a resin film, and is not particularly limited, and the range of the adhesive force of the protective film 600 may vary depending on the characteristics of the substrate to be protected or the thickness of the substrate. And can be variable.

Referring to FIG. 14, in a state where the protective film 600 is formed as shown in FIG. 13, a shadow mask on the exposed pads 17R, 17G, 17B for metal deposition for expansion of the pads 17R, 17G, 17B Place (700, Shadow Mask).

The shadow mask 700 may have an exposed pattern shape in a portion requiring metal deposition to form an extended pad.

Referring to FIG. 15, a state in which metal deposition is performed in a state in which the shadow mask 700 is aligned is shown. Metal deposition may be deposited by electron beam evaporation or sputtering, but is not limited thereto. At this time, the used metal (electrode metal) may be composed of one or more thin film layers. In the case of one layer, gold (Au, Gold), silver (Ag, Silver), copper (Cu, Copper), chromium (Cr, Chromium), nichrome (NiCr, Nickel Chromium) or titanium (Ti, Titanium), palladium It may be (Pd, Palladium), aluminum (Al, Aluminum), or the like. In the case of two layers, various combinations of Cr/Au, Ti/Au, Ti/Al, etc. In the case of three layers, various combinations of Ti/Cr/Au and Ti/Al/Au may be used.

Expansion pads 18R, 18G, and 18B may be formed as upper surfaces of each of the pads 17R, 17G, and 17B by metal deposition through the opened portion of the shadow mask 700.

In this state, as shown in FIG. 16, when the shadow mask 700 is removed, the expansion pads 18R, 18G, and 18B having an extended area from the pads 17R, 17G, and 17B respectively formed in the RGB of the existing pixel CSP are Can be formed.

The extended area means a restricted area that can be extended within one pixel CSP, and is an area extending from the pads 17R, 17G, 17B of the RGB pixel 100', and does not cross adjacent extended areas. It means that it is an area that is not.

When the protective film 600 is removed from the pixel CSP 400 in the process of FIG. 16, the expansion pads whose size is enlarged from the electrode pads 17R, 17G and 17B of the plurality of pixels CSP 400 arranged in a matrix ( 18R, 18G, 18B) array of pixel CSPs 400 and each one pixel CSP 400 can be obtained.

The array of pixel CSPs 400 having the expansion pads 18R, 18G, and 18B and each of the pixel CSPs 400 may be transferred to a display panel to implement a large display device.

17 illustrates a plan view of a pixel CSP including an expansion pad as an example.

As shown in FIG. 17, it can be seen that the pads 17R, 17G, 17B of the pixel CSP 400 are extended to the expansion pads 18R, 18G, 18B on a plane basis. It means that it is extended, and it means that the connection cross-sectional area between the pads can be increased as the surface area of the pads increases.

Pads 17R, 17G, 17B and expansion pads 18R, 18G, 18B mean a first electrode, pads 17R', 17G', 17B' and expansion pads 18R', 18G', 18B' May mean a second electrode.

The expansion pads 18R, 18G, 18B are expanded from the electrode pads 17R, 17G, and 17B formed on the RGB pixel 100' by utilizing the existing redundant area that has not been used within one pixel CSP 400 area. The cross-sectional area may have an enlarged shape. In particular, in the case of micro-unit LED chips, since the pixel unit is 30㎛ * 30㎛ to 100㎛ * 100㎛, the width and length of the pads are also very fine, and electrical open occurs during the surface mounting process of these as the substrate of the display panel. Therefore, the defective rate is very high. On the other hand, by performing the surface mounting process on the display panel in units of pixel CSP that can be expanded, the electrical connection process of micro LEDs in tens of um area is scaled up to the electrical connection process of pixel CSPs in several hundreds of um area. It can minimize the defects of the back. In addition, it is possible to minimize electrical defects by increasing an alignment margin between the pixel CSP pad and the display panel pad during the surface mounting process on the display device, and to rapidly manufacture a large-area display device.

18 to 20 are diagrams for explaining in detail a step 170 of transferring the pixel CSP array formed on the transfer frame shown in FIG. 1 to a carrier substrate. The step 170 of transferring the pixel CSP array formed on the transfer frame to the carrier substrate may be referred to as'primary transfer'.

FIG. 18 shows three pixel CSPs 400P1, 400P2 including protective layers 500P1, 500P2, and 500P3 encapsulating three RGB pixels 100'P1, 100'P2, and 100'P3 in FIG. 400P3) and a cross-sectional view of a portion of the transfer frame 200.

Referring to FIG. 18, a first pixel CSP 400P1 is encapsulated in a first opening of a transfer frame 200 by a first protective layer 500P1, and a second pixel CSP 400P2 is a second protection layer. The layer 500P2 is encapsulated in the second opening of the transfer frame 200, and the third pixel CSP 400P3 is inserted into the third opening of the transfer frame 200 by the third protective layer 500P3. It is encapsulated.

Next, referring to FIG. 19, a carrier substrate 900 is attached to the upper surface of the transfer frame 200 and the upper surfaces of the first to third protective layers 500P1, 500P2, and 500P3. Here, the carrier substrate 900 is for extracting the corresponding protective layers 500P1, 500P2, 500P3 encapsulating each pixel CSP (400P1, 400P2, 400P3) from the plurality of openings 210 of the transfer frame 200. will be. Here, the carrier substrate 900 may also be referred to as a'transfer adhesive member'. The carrier substrate may also be referred to as a transfer adhesive member, and an adhesive or adhesive is applied to these materials such as PET, PP, PE, PS resin plates, or these materials have a thin thickness in the form of a tape and are Adhesives or adhesives may be applied.

Next, referring to FIG. 20, the transfer frame 200 is removed. If the adhesion between the carrier substrate 900 and each protective layer (500P1, 500P2, 500P3) is greater than the adhesion between the transfer frame 200 and each protective layer (500P1, 500P2, 500P3), only the transfer frame 200 is carrier It can be removed from the substrate 900 and the plurality of protective layers 500P1, 500P2, and 500P3. Therefore, it is preferable that the carrier substrate 900 has an adhesive force greater than that between the transfer frame 200 and each of the protective layers 500P1, 500P2, and 500P3.

Meanwhile, the carrier substrate 900 may be referred to as a second transfer medium in the method of manufacturing a display device according to an embodiment of the present invention. The second transfer medium and the protective layer have a second adhesive force greater than the first adhesive force. Accordingly, the above-described primary transfer step may be a step of transferring the pixel CSP array formed on the first transfer medium from the first transfer medium to a second transfer medium having a second adhesive force greater than the first adhesive force. For example, the second adhesive force may be several hundred times greater than the first adhesive force. More specifically, the first adhesive force may be 5 gf/25mm to 15 gf/25mm, and the second adhesive force may be 2,000 gf/25mm to 4,000 gf/25mm. More preferably, the first adhesive force may be 10 gf/25mm, and the second adhesive force may be 3,000 gf/25mm.

21 to 25 are diagrams for explaining in detail a step 190 of transferring the pixel CSP array transferred to the carrier substrate shown in FIG. 1 to the display panel.

21 is a view for explaining the structure of the display panel 1100, FIG. 21(a) is an enlarged plan view of a part of the display panel 1100, and FIG. 21(b) is a view of FIG. 21(a) ) Is a side view.

Referring to FIG. 21, the display panel 1100 includes a plurality of pads 1150 electrically connected to the pads of the plurality of pixel CSPs 400P1, 400P2, and 400P3 shown in FIG. 20.

A plurality of pads 1150 may be arranged on the upper surface of the display panel 1100. The plurality of pads 1150 are arranged in row and column directions for each of the plurality of pad groups. Each pad group includes a plurality of pads electrically connected to one pixel CSP. Here, the number of pads may be 6, but is not limited thereto, and the number of pads may vary according to the number of pads formed in one pixel CSP. Here, the pitch between the plurality of pad groups may be the same as the distance between the plurality of openings 210 of the transfer frame 200 shown in FIG. 7.

Next, referring to FIG. 22, a solder paste 1200 is applied on a plurality of pads 1150 of the display panel 1100. The solder paste 1200 may be applied on the plurality of pads 1150 of the display panel 1100 through various methods such as screen printing, dispensing, and jetting.

Next, referring to FIG. 23, a plurality of protective layers 500P1, 500P2 attached to the carrier substrate 900 and the carrier substrate 900 manufactured in FIG. 20 and having pixel CSPs 400P1, 400P2, 400P3 therein. , 500P3) on the display panel 1100, and the pad 17 of each pixel CSP (400P1, 400P2, 400P3) in contact with the solder paste 1200 applied on the pad 1150 of the display panel 1100 Let it.

After the pad 17 of the pixel CSP (400P1, 400P2, 400P3) and the pad 1150 of the display panel 1100 are in contact with each other through the solder paste 1200, for example, a self-aligning paste (SAP) ) When a predetermined heat is applied using a soldering method, the solder particles contained in the solder paste 1200 are the pads 17 of the pixel CSPs (400P1, 400P2, 400P3) and the pads of the display panel 1100. It can be self-assembly between (1150). Meanwhile, the thermosetting resin included in the solder paste 1200 may be cured by heat.

Next, referring to FIG. 24, when the pads 17 of the pixel CSPs 400P1, 400P2, and 400P3 and the pads 1150 of the display panel 1100 are soldered, the carrier substrate 900 is formed with a plurality of protective layers 500P1. , 500P2, 500P3). Here, the soldering adhesion between the pad 17 of the pixel CSP (400P1, 400P2, 400P3) and the pad 1150 of the display panel 1100 is between the carrier substrate 900 and each of the protective layers 500P1, 500P2, and 500P3. Since it is much larger than the adhesive force, only the carrier substrate 900 can be easily separated.

FIG. 25 is a plan view showing that a plurality of protective layers 500P1, 500P2, and 500P3 encapsulating one pixel CSP shown in FIG. 24 are transferred to the display panel 1100 along a plurality of row and column directions. .

Meanwhile, the solder paste 1200 may be referred to as a third transfer medium in the method of manufacturing a display device according to an embodiment of the present invention. The third adhesive force, which is the soldering adhesive force between the third transfer medium and the pad of the pixel CSP, is greater than the second adhesive force. Accordingly, the above-described secondary transfer step may be a step of transferring the pixel CSP array transferred to the second transfer medium to a third transfer medium having a third adhesive force greater than the second adhesive force applied to the display panel. For example, the third adhesion may be thousands of times greater than the second adhesion. More specifically, the second adhesive force may be 2,000 gf/25mm to 4,000 gf/25mm, and the third adhesive force may be 800,000 gf/25mm to 1,200,000 gf/25mm. More preferably, the second adhesive force may be 3,000 gf/25mm, and the third adhesive force may be 1,000,000 gf/25mm.

It is a task to be achieved by the present invention to implement the third adhesive force to have a significant adhesive force that is hundreds to thousands of times larger than the first adhesive force for the second adhesive force than for the second adhesive force so that simultaneous transfer to all pixel CSPs can be completed. , This has the advantage of maximizing the transfer success rate by using the bonding force of the adhesive force itself, rather than the concept of transferring by controlling the physical force or adhesive force such as electrostatic attraction. Here, the meaning of controlling the adhesive force means controlling the adhesive force by controlling certain conditions such as exposure, temperature, and heat, and in the embodiment of the present invention, the adhesive force is not controlled, but the difference in the adhesive force between the transfer media is used.

The number of openings 210 of the transfer frame 200 illustrated in FIG. 7 and the number of pixel CSPs 400 formed in the display panel 1100 illustrated in FIG. 25 are illustrated to correspond to each other, but the present invention is not limited thereto. . For example, in order to manufacture a large-area display panel, the transfer frame 200 may be repeatedly used two or more times on one large-area display panel. This has the advantage of being able to quickly manufacture a large-area display panel.

Meanwhile, the pixel CSP array including the expansion pads 18R, 18R', 18G, 18G', 18B, 18B' shown in FIG. 17 may be transferred to the carrier substrate through the method shown in FIGS. 18 to 20.

Further, the pixel CSP array including the expansion pads 18R, 18R', 18G, 18G', 18B, 18B' transferred to the carrier substrate may be transferred to the display panel as shown in FIGS. 21 to 25. Here, when configuring a display or a device by moving the pad area of the display panel, it is possible to solve an electrical connection problem (opening, sorting failure) occurring in a conventional surface mounting process of a chip unit. Specifically, by simultaneously introducing a pad-extended pixel CSP and a region-shifted pad (target substrate), the electrical connection process of the micro LED in a tens of µm area is scaled up to a pixel CSP electrical connection process in a hundreds of µm area. , It is possible to scale up the electrical connection process of the mini LED of several hundreds µm area to the pixel CSP electrical connection process of several mm area. Through this scale-up, it is possible to quickly manufacture a large-area display device by preventing an open/short defect between electrodes in a transfer process constituting a display device and increasing alignment margin. Hereinafter, it will be described in detail with reference to FIGS. 26 to 27.

26 is a view showing a comparison before and after movement of an electrode pad of a display panel.

26 shows a pad array of a display panel, which may have an arrangement corresponding to a plurality of pads of one pixel CSP 400P1.

26(A1), (B1), and (C1) are schematic diagrams of arrangement of pads on a conventional display panel, and (A2), (B2), and (C2) are arrangements of pads on a display panel according to an embodiment of the present invention. Yes.

In the case of micro LEDs and mini LEDs, since the sizes are very small, the distance d1 between pads of the display panel corresponding thereto is also very narrow. In the embodiment of the present invention, by increasing the spacing d2 between pads of the display panel, it is possible to prevent a short circuit due to solder paste between the pads in advance.

The relationship between the pads d1 <d2 is established, and d2 can be implemented by moving regions left and right from respective positions of the pads 720 and 720'.

Prerequisites for increasing the spacing between the pads 720 and 720' of the display panel are as follows.

An embodiment of the present invention proposes a first transfer and a second transfer as a method for simultaneously transferring a plurality of pixel CSPs 400 to the display panel 700 at a high speed. Here, for the second transfer, a transfer method using a difference in adhesion between the carrier substrate 900 and the solder paste 740 is adopted.

Therefore, in order to implement the second transfer, the solder paste 740 must be applied on the pad 720 of the display panel 700, and in this case, before the solder paste 740 is applied, the white ink ( White ink) is applied first.

If the distance between the pads 72 and 72' of the display panel is very narrow (less than 100㎛) as in the prior art, white ink 73 cannot be filled between the pads 72 and 72', and white ink A step is formed between the pads 72 and 72' that are not filled with the 73, so that the solder paste 74 is trapped, and a short circuit may occur due to the remaining solder paste.

Accordingly, the embodiment of the present invention increases the distance d2 between the pads 720 and 720 ′ by moving the pads 720 and 720 ′ of the display panel 700 left and right to solve the above problem. A white ink dam can be formed by the white ink 730. That is, the gap between the pads 720 and 720 ′ is widened, so that white ink may be filled between the pads.

With the formation of the white ink dam, a step difference between the pads 720 and 720 ′ may be eliminated, and a cause of a short circuit between electrodes may be eliminated due to the absence of residual solder paste.

Next, as described above, if the electrode spacing is widened according to the precondition for increasing the spacing of the pads 720 and 720' of the display panel, the possible conditions for increasing the electrode spacing are as follows.

The possible conditions for increasing the spacing of the pads 720 and 720' of the display panel 700 are the pads 17R, 17R', 17G, 17G', 17B and 17B of the pixel CSP 400 as in FIG. 17 described above. ') is possible by the extended expansion pads 18R, 18R', 18G, 18G', 18B, 18B'.

FIG. 27 is a diagram for describing in detail a step of transferring a pixel CSP array having expansion pads transferred to a carrier substrate to a display panel.

Referring to FIG. 27A, a solder paste 740 is applied on a plurality of pads 720 of the display panel 700. The solder paste 740 may be applied on the plurality of pads 720 of the display panel 700 through various methods such as screen printing, dispensing, and jetting.

Next, referring to FIG. 27B, a plurality of protective layers 500 attached to the carrier substrate 900 and the carrier substrate 900 and having a pixel CSP therein are transferred onto the display panel 700. , The expansion pads 18R and 18R' of each pixel CSP are brought into contact with the solder pastes 740 and 740' applied on the pads 720 and 720' of the display panel 700.

After the expansion pads 18R and 18R' of each pixel CSP and the pads 720 and 720' of the display panel 700 are in contact with each other through the solder pastes 740 and 740', for example, a self-aligning paste (Self Align Paste, SAP) When a predetermined heat is applied using a soldering method, solder particles contained in the solder pastes 740 and 740' are removed from the expansion pads 18R and 18R' of the pixel CSP and the display panel ( It may be self-assembled between the pads 720 and 720' of 700).

Meanwhile, the thermosetting resin included in the solder pastes 740 and 740' may be cured by heat.

Next, referring to (C) of FIG. 27, when the expansion pads 18R and 18R' of the pixel CSP and the pads 720 and 720' of the display panel 700 are soldered, the carrier substrate 900 is It is removed from the protective layer 500.

Here, since the soldering adhesive force between the expansion pads 18R and 18R' of the pixel CSP and the pads 720 and 720' of the display panel 700 is much larger than the adhesive force between the carrier substrate 900 and the protective layer 500 , Only the carrier substrate 900 can be easily separated.

Referring to FIG. 27, the display panel is formed by the first and second pads 17R and 17R' of the pixel CSP, and expansion pads 18R and 18R' formed on the first and second pads 17R and 17R'. The spacing between the pads 720 and 720 ′ of 700) can be widely adjusted, that is, the area of the pads 720 and 720 ′ can be moved.

That is, it is possible to improve the contact margin between the electrodes between the pixel CSP and the display panel 700 during the transfer process by the expansion pads 18R and 18R', and both of the pads 720 and 720' of the display panel 700 Since it is possible to move the area such as spreading, it is possible to block the occurrence rate of a short between electrodes. In particular, when the contact margin is secured and the short circuit is prevented, it is possible to improve the speed and accuracy of the transfer process when applied to a display device to which a micro-unit LED or a mini-unit LED is applied.

Again, referring to FIG. 1, although not shown in FIG. 1, a rework step may be further included. The rework step is a step of removing a pixel CSP determined to be malfunctioning or defective from among the pixel CSPs formed in the display panel 1100 shown in FIG. 25 and placing a new pixel CSP at the position of the removed pixel CSP. A new pixel CSP that is normally operating may be located using a pick and place device (not shown). By further proceeding with the rework step, since the malfunction or defective pixel CSP is removed, and a new pixel CSP is filled in the place where the defective pixel CSP was to be located in the display panel, compared to the method of manufacturing the display device shown in FIG. There is an advantage of remarkably reducing the defects of (1100).

Features, structures, effects, and the like described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Further, the features, structures, effects, and the like illustrated in each embodiment can be implemented by combining or modifying other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Accordingly, contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention pertains will not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications not illustrated are possible. For example, each constituent element specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

200: transcription frame
300: substrate
400: Pixel CSP
500: protective layer
900: carrier substrate
1100: display panel

Claims (14)

Forming a plurality of RGB pixels on a wafer, forming a plurality of RGB pixels;
Dicing the wafer on which the plurality of RGB pixels are formed for each of the RGB pixels;
Forming a pixel CSP array in the transfer frame by disposing one diced RGB pixel for each of a plurality of openings arranged in an array form in a transfer frame and encapsulating each of the RGB pixels to form a pixel CSP array in the transfer frame;
Depositing a metal so as to extend horizontally from one surface of each pad of the pixel CSP in the pixel CSP array formed on the transfer frame to form an extended pad extending the length or area of each pad;
A carrier substrate is adhered to the pixel CSP array and the transfer frame, and a first adhesion force between the pixel CSP array and the transfer frame, and a second adhesion force between the pixel CSP array and the carrier substrate greater than the first adhesion force A primary transfer step of transferring the pixel CSP array from the transfer frame to the carrier substrate by using the difference of; And
Including; a secondary transfer step of transferring the pixel CSP array transferred to the carrier substrate to the display panel,
The first adhesive force is 5 gf/25mm to 15 gf/25mm, the second adhesive force is 2,000 gf/25mm to 4,000 gf/25mm, and the first adhesive force and the second adhesive force are not controlled by light, temperature or heat. ,
Forming the expanded pad,
Attaching a protective film to one surface of the transfer frame;
Depositing a metal in a region extending from the pad by attaching a shadow mask to the other surface of the transfer frame on the pad side of the pixel CSP;
Including; removing the shadow mask,
The protective film is attached to a side opposite to which the pad is formed, while the pad is exposed.
The method of claim 1, wherein the forming of the plurality of RGB pixels comprises:
Forming a plurality of light emitting devices on the wafer; And
Forming at least one color conversion layer on some of the plurality of light emitting devices;
Containing, a method of manufacturing a display device.
The method of claim 1, wherein the forming of the plurality of RGB pixels comprises:
Growing an epitaxial layer on one surface of the wafer;
Forming a pad on the epitaxial;
Forming a protective layer for passivating the epi and the pad, wherein the pad is exposed to the outside of the protective layer;
Forming a blocking dam on the other side of the wafer, and forming an opening positioned on the epi in the blocking dam; And
Forming a color conversion layer in the opening;
Containing, a method of manufacturing a display device.
The method of claim 1,
A method of manufacturing a display device, wherein a pitch between the plurality of openings of the transfer frame is the same as a pitch between the pixel CSP arrays to be transferred to the display panel.
The method of claim 1, wherein the step of forming the pixel CSP array comprises:
Disposing a substrate under the transfer frame to close a lower opening of each of the plurality of openings;
Arranging the RGB pixels on the substrate inside the plurality of openings;
Filling and curing a protective layer encapsulating the RGB pixels in the plurality of openings; And
Removing the substrate from the transfer frame, the plurality of RGB pixels, and the protective layer;
Containing, a method of manufacturing a display device.
delete The method of claim 1, wherein the secondary transfer step,
Applying a solder paste on a plurality of pads of the display panel;
Soldering the extended pads of the pixel CSP array transferred to the carrier substrate by contacting the applied solder paste; And
Separating the carrier substrate from the pixel CSP array;
Containing, a method of manufacturing a display device.
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