KR102203639B1 - Method for manufacturing display apparatus and display apparatus - Google Patents

Abstract

The present invention relates to a manufacturing method of a display apparatus and a display apparatus and, more specifically, to a manufacturing method of a display apparatus and a display apparatus manufactured by the same which can selectively transfer multiple RGB pixels formed on a wafer to a display panel quickly and efficiently. According to an embodiment of the present invention, the manufacturing method of a display apparatus comprises: a multiple-RGB pixel forming step of forming multiple RGB pixels on a wafer; a dicing step of dicing the wafer on which the multiple RGB pixels are formed for each of the RGB pixels; a primary transfer step of transferring a pixel CSP array including a plurality of the diced RGB pixels to a carrier substrate; and a secondary transfer step of selectively 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 selectively transferring a plurality of RGB pixels formed from a wafer to a display panel quickly and efficiently, and It relates to a display device.

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.

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

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, it provides a method of manufacturing a display device capable of manufacturing a display device having a variety of sizes and pitches between pixels.

In addition, a method of manufacturing a display device capable of using a wafer including as many RGB pixels as possible on a limited area regardless of the resolution of the display device is provided.

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; Dicing the wafer on which the plurality of RGB pixels are formed for each of the RGB pixels; A first transfer step of transferring a pixel CSP array including a plurality of diced RGB pixels to a carrier substrate; And a second transfer step of selectively transferring the pixel CSP array transferred to the carrier substrate to a display panel.

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

If the method of manufacturing a display device according to the embodiment is used, there is an advantage in that a plurality of RGB pixels in the form of a single chip on a wafer can be selectively transferred to a display panel quickly and efficiently.

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 one by one of the micro-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, there is an advantage of being able to manufacture a display device having various sizes and various pitches between pixels.

In addition, since a wafer having as many RGB pixels as possible on a limited area is used regardless of the resolution of the display device, there is an advantage of reducing the wafer manufacturing cost.

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 7 are views for explaining an embodiment of steps 110 and 130 shown in FIG. 1.
8 are cross-sectional views for comparing a pixel CSP having conventional general pads 17r and 17r' in which pads are not expanded and a pixel CSP having extended pads 17R and 17R'.
9 is a front view showing that a pixel CSP array having a conventional general pad is formed on a wafer 10'.
10 is a front view showing that a pixel CSP array with extended pads is formed on a wafer 10'.
FIG. 11 is a diagram for describing in detail the step 150 of transferring the pixel CSP array shown in FIG. 1 to a carrier substrate.
12 to 16 are diagrams for explaining in detail a step 170 of transferring the pixel CSP array transferred to the carrier substrate shown in FIG. 1 to the display panel.
FIG. 17 is a diagram illustrating that the remaining pixel CSP arrays are transferred to a display panel 1100' different from the display panel 1100 shown in FIG. 16.
18 is an exemplary diagram for explaining a method of manufacturing a large-area display device by using the display manufacturing method according to an embodiment of the present invention.
19 is a view showing a comparison before and after movement of an electrode pad of a display panel.
20 is a diagram for explaining in detail a step of transferring a pixel CSP array having an extended pad 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 the CSP array to the carrier substrate 150 and selectively transferring the pixel CSP array transferred to the carrier substrate to the display panel (170). Steps 110, 130, 150, and 170 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 7 are views 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.

In FIG. 3, a pitch (W Pitch) between one group including a plurality of epis 11 ′, for example, three epis 11 ′ and another adjacent group, is shown in the display panel shown in FIG. 12 to be described later. A pitch between adjacent pixel CSPs to be transferred may have a relationship according to Equation 1 below.

In Equation 1, K is a natural number of 1 or more.

According to Equation 1, if K is 1, the pitch between neighboring groups (W Pitch) may be the same as the pitch (D Pitch) between neighboring pixel CSPs to be transferred to a display panel to be described later. When K is greater than 1, a pitch between neighboring groups (W Pitch) may be smaller than a pitch (D Pitch) between neighboring pixel CSPs to be transferred to a display panel to be described later.

In FIG. 3, the pad 17 may be manufactured in an expanded form unlike a conventional general pad. In other words, during the process of forming the pad PAD on the wafer 10 ′, an extended pad having a size larger than that of a conventional pad may be formed. In the following drawings including FIG. 3, the pad 17 having an extended size is illustrated, but it is not limited thereto, and it should be noted that a conventional pad may be substituted for the extended size pad 17. .

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. Here, a space in which the blocking dam 20 is to be disposed may be formed in the wafer 10 ′ by trenching portions of the wafer 10 ′, and a blocking dam 20 may be formed thereon.

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, an encapsulation layer 19 is formed on the blocking dam 20. The encapsulation layer 19 may serve to protect the encapsulated color conversion layers 15R' and 15G' from the outside. Here, the encapsulation layer 19 may be formed in some of the plurality of openings 20h in which the color conversion layer is not formed.

Referring to FIG. 7, as shown in FIGS. 3 to 6, the epitaxial 11', the color conversion layers 15R' and 15G', and the encapsulation layer 19 are formed on the wafer 10'. Each RGB pixel 100' is diced to form a plurality of RGB pixels 100'. Here, there may be several methods of dicing for each RGB pixel 100 ′, but dicing may be performed using a laser as an example.

In the following drawings, one RGB pixel 100 ′ is illustrated as the RGB pixel 100 ′ formed in FIG. 7, but is not limited thereto, and may be a single RGB pixel 100 diced in FIG. 2. have.

One RGB pixel 100' may have a flip chip structure that does not require a wire. Electrical connection is possible with pads 17 instead of wires. One RGB pixel 100 ′ may emit light of various colors according to an external control signal through the pad 17.

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' 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. A pixel CSP array may be formed by arranging a plurality of RGB pixels 100 ′ on a carrier substrate in a row and column direction, and a pixel CSP array arranged on the carrier substrate may be selectively transferred to a display panel to be described later. .

In one RGB pixel 100', the plurality of pads 17 may vary depending on the number of light emitting units included in one RGB pixel 100'. For example, one RGB pixel 100' If the number of light-emitting units included in is three, since two pads are required for each light-emitting unit, a total of six pads may be formed, or if the (+) electrode is a common electrode, a total of four pads may be formed.

8 is a side cross-sectional view for comparing a pixel CSP having a conventional general pad 17r, 17r' in which the pad is not extended and a pixel CSP having extended pads 17R, 17R', and FIG. 9 is a conventional It is a front view showing that a pixel CSP array having a general pad is formed on the wafer 10', and FIG. 10 is a front view showing that a pixel CSP array having an extended pad is formed on the wafer 10'.

When comparing (a) and (b) of FIGS. 8 and 9 and 10, the pads 17R and 17R' expanded in the wafer manufacturing process are conventional, which are not used within one pixel CSP 100'. It is designed in an expanded form with the RGB pixels in mind by utilizing the redundant area, and is enlarged compared to the pads 17r and 17r' of the existing chip, so that the cross-sectional area can be enlarged. In particular, in the case of a micro-unit LED chip, the pixel unit is 30 µm * 30 µm to 100 µm * 100 µm (50 µm * 50 µm in Figs. 12 and 13), so the width or length of the pad is also very fine, and displays these The defect rate is very high due to electrical open, etc. during the surface mounting process with the panel substrate. 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 pad of the display panel during the surface mounting process on the display device, and to quickly manufacture a large-area display device.

FIG. 11 is a diagram for describing in detail the step 150 of transferring the pixel CSP array shown in FIG. 1 to a carrier substrate. The step 150 of transferring the pixel CSP array to the carrier substrate may be referred to as'primary transfer'.

Referring to FIG. 11, a carrier substrate 900 is attached to an upper surface of a plurality of pixel CSPs 100'P1, 100'P2, 100'P3, and 100'P4. Specifically, the carrier substrate 900 may be attached to the upper surface of each encapsulation layer 19 of the plurality of pixel CSPs 100'P1, 100'P2, 100'P3, 100'P4. Here, the carrier substrate 900 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. While having, an adhesive or adhesive may be applied to one side thereof.

The carrier substrate 900 may have a predetermined softness. The carrier substrate 900 having a predetermined softness may be formed of a material that can be easily bent by an external force. If the carrier substrate 900 is a material that can be easily bent, the transfer efficiency can be further improved compared to the case where the carrier substrate 900 is a material that is not easily bent. When the carrier substrate 900 is made of a material that is not easily bent, after attaching a plurality of pixel CSPs (100'P1, 100'P2, 100'P3, 100'P4) to the carrier substrate, the carrier substrate is lifted at once. It is difficult. The reason is that the adhesion between the plurality of pixel CSPs 100'P1, 100'P2, 100'P3, 100'P4 and the carrier substrate 900 is significant. However, if the carrier substrate 900 is a material that can be easily bent, after attaching a plurality of pixel CSPs 100'P1, 100'P2, 100'P3, 100'P4 to the carrier substrate 900, the carrier substrate 900 If only one portion of) is raised upward, the number of pixel CSPs attached only to that portion is relatively small, so that the entire carrier substrate 900 can be easily lifted with a small force.

In addition, the carrier substrate 900 may be a transparent material. When the carrier substrate 900 is a transparent material, when transferring a plurality of pixel CSPs (100'P1, 100'P2, 100'P3, 100'P4) to the carrier substrate 900, position adjustment and distortion are prevented to the outside. There is an advantage that can be adjusted or controlled through the equipped vision system (not shown).

Meanwhile, the carrier substrate 900 may also be referred to as a first transfer medium in a method of manufacturing a display device according to an embodiment of the present invention. A first adhesive force is formed between the first transfer medium and the pixel CSP array. Specifically, the first adhesive force may be 2,000 gf/25mm to 4,000 gf/25mm. More preferably, the first adhesive force may be 3,000 gf/25mm.

12 to 16 are diagrams for explaining in detail a step 170 of selectively transferring the pixel CSP array transferred to the carrier substrate shown in FIG. 1 to the display panel.

12 is a view for explaining the structure of the display panel 1100, FIG. 12(a) is an enlarged plan view of a part of the display panel 1100, and FIG. 12(b) is a view of FIG. 12(a) ) Is a side view.

Referring to FIG. 12, a display panel 1100 is a pad electrically connected to each pad 17 of a plurality of pixel CSPs 100'P1, 100'P2, 100'P3, 100'P4 shown in FIG. (1150) includes a large number.

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 (D Pitch) between the plurality of pad groups is the relationship between the one group including the plurality of epis 11' shown in FIG. 3 and the pitch between the neighboring other groups (W Pitch) and the above-described Equation 1 Can have

Next, referring to FIG. 13, 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. 14, the carrier substrate 900 manufactured in FIG. 11 and the pixel CSPs 100'P1, 100'P2, 100'P3, 100'P4 attached to the carrier substrate 900 are displayed on a display panel. (1100), move the pads 17 of some CSPs (100'P1, 100'P3) among all the pixel CSPs (100'P1, 100'P2, 100'P3, 100'P4) to the display panel 1100 The solder paste 1200 applied on the pad 1150 of FIG. Since the solder paste 1200 does not exist under the remaining CSPs 100'P2 and 100'P4, the pads 17 of the remaining CSPs 100'P2 and 100'P4 can come into contact with the solder paste 1200. none.

After the pads 17 of some of the pixels CSPs 100'P1 and 100'P3 are in contact with the pads 1150 of the display panel 1100 through the solder paste 1200, for example, self-alignment paste Paste, SAP) When a predetermined heat is applied using a soldering method, solder particles contained in the solder paste 1200 are displayed with the pads 17 of some of the pixels CSPs (100'P1, 100'P3). It may be self-assembly between the pads 1150 of the panel 1100. Meanwhile, the thermosetting resin included in the solder paste 1200 may be cured by heat.

Next, referring to FIG. 15, when the pads 17 of some of the pixels CSPs 100'P1 and 100'P3 and the pads 1150 of the display panel 1100 are soldered, the carrier substrate 900 is converted to some of the pixels CSPs. It is removed from each of the encapsulation layers 19P1 and 19P3 of (100'P1, 100'P3). Here, the soldering adhesive force between the pad 17 of some of the pixel CSPs 100'P1, 100'P3 and the pad 1150 of the display panel 1100 is the carrier substrate 900 and each encapsulation layer 19P1, 19P3. ), it is possible to easily separate only the carrier substrate 900 and the remaining pixel CSPs 100'P2 and 100'P4. Since the remaining pixel CSPs 100'P2 and 100'P4 are not soldered with the pads 1150 of the display panel 1100, they are attached to the carrier substrate 900 and separated together with the carrier substrate 900.

FIG. 16 shows that encapsulation layers 19P1 and 19P3 encapsulating some of the pixels CSPs 100'P1 and 100'P3 shown in FIG. 15 are transferred to the display panel 1100 along a plurality of row and column directions. It is a plan view showing what has been done.

FIG. 17 shows a plurality of row and column directions in the display panel 1100' in which the encapsulation layers 19P2 and 19P4 encapsulating the remaining pixels CSPs 100'P2 and 100'P4 shown in FIG. It is a plan view showing what was transferred along.

Referring to FIGS. 16 and 17 together, the remaining pixels CSPs 100'P2 and 100'P4 that are not soldered to the display panel 1100 in FIG. 15 and are continuously attached to the carrier substrate 900 are shown in FIG. By removing the carrier substrate 900 after soldering to the pads of the other display panel 1100 ′ in the same manner as described above, two or more display panels 1100 are formed with a plurality of pixel CSPs attached to one carrier substrate 900. , 1100') can be prepared. Therefore, since the selective transfer method according to the embodiment of the present invention has an advantage in the process of performing two or more secondary transfers with a single primary transfer, there is an advantage of remarkably shortening the display manufacturing process time. .

18 is a view for explaining a method of manufacturing a large-area display panel 1100 ″ by using the display manufacturing method according to an embodiment of the present invention.

Referring to FIG. 18, a large-area display panel 1100 ″ is divided into a plurality of parts, and as shown in FIG. 16, some pixels CSPs 100'P1, 100 'P3) may be transferred, and the remaining pixels CSPs 100'P2 and 100'P4 may be transferred to another part as shown in FIG. 17. By transferring the remaining parts in this way, there is an advantage in that the large-area display panel 1100 ″ can be transferred by quickly improving the transfer rate.

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

It is a task to be achieved by the present invention to implement the second adhesive force to have a significant adhesive force that is hundreds to thousands of times larger than the first adhesive force so that selective transfer to some of the pixel CSPs can be performed, and this is an electrostatic attraction, etc. It 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 of 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.

Meanwhile, referring again to FIG. 1, in the manufacturing method of the display device according to the embodiment of the present invention described above, the first transfer step 150 may be omitted. In other words, a plurality of diced pixel CSPs may be transferred directly to the display panel without the carrier substrate 900.

For example, if the one shown in FIG. 6 is turned over and diced as shown in FIG. 7 to form a plurality of pixel CSPs, and then the display panel shown in FIG. 12 is moved onto the formed plurality of pixels CSPs to perform soldering, Some of the pixel CSPs in contact with the solder paste will be soldered to the display panel, and the remaining pixel CSPs that are not in contact will remain in place.

Here, another display panel as shown in FIG. 17 may be manufactured by soldering another display panel on the remaining pixel CSP, or a large-area display panel as illustrated in FIG. 18 may be manufactured.

Meanwhile, 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 the conventional surface mounting process of a chip unit. Specifically, by simultaneously introducing a pixel CSP having an extended pad and a region-shifted pad (target substrate), the electrical connection process of the micro LED in a tens µm area is scaled up to a pixel CSP electrical connection process in a hundreds µm area. )can do. 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. 19 to 20.

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

19 illustrates a pad array of a display panel, which may have an arrangement corresponding to a plurality of pads of one pixel CSP 100'P1 illustrated in FIG. 7.

(A1), (B1), and (C1) of FIG. 19 are schematic diagrams of an 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 the micro LED, since the size is very small, the spacing d1 between the 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.

The embodiment of the present invention proposes a first transfer and/or a second transfer as a method for simultaneously transferring a plurality of pixel CSPs 100' shown in FIG. 7 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 condition for increasing the spacing of the pads 720 and 720' of the display panel 700 is that the pads 17R, 17R', 17G, and 17B of the pixel CSP 400 are as shown in FIGS. 7 and 8 described above. It is possible by being extended.

20 is a diagram for explaining in detail a step of transferring a pixel CSP array having an extended pad transferred to a carrier substrate to a display panel.

Referring to FIG. 20A, 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. 20B, the carrier substrate 900 and the encapsulation layer 19 attached to the carrier substrate 900 and having RGB pixels therein are moved onto the display panel 700. , The pads 17R and 17R' 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 pads 17R and 17R' 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, self-alignment paste 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 pads 17R and 17R' of the pixel CSP and the display panel 700. It can be self-assembled between the pads 720 and 720' of.

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

Next, referring to FIG. 18C, when the pads 17R and 17R' of the pixel CSP and the pads 720 and 720' of the display panel 700 are soldered, the carrier substrate 900 is encapsulated. Peel off from layer 19.

Here, the soldering adhesive force between the pads 17R and 17R' 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 encapsulation layer 19 Therefore, only the carrier substrate 900 can be easily separated.

Referring to FIG. 20, it is possible to widely adjust the spacing between the pads 720 and 720 ′ of the display panel 700 by the first and second pads 17R and 17R ′ of the pixel CSP, that is, the pad 720 , 720') can be moved.

In other words, 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 pads 17R and 17R' that are expanded than the conventional pads, and the pad 720 of the display panel 700, 720'), it is possible to move the same area as the spread of both sides, so that it is possible to block the occurrence rate of a short between electrodes. In particular, such contact margin and short-circuit prevention can improve the speed and accuracy of the transfer process when applied to a display device to which a micro-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 to remove the pixel CSP determined to be malfunctioning or defective among the pixel CSP arrays formed on the display panels 1100, 1100', and 1100'' shown in FIGS. 16 to 18, and remove the new pixel CSP. This is the step of placing in. 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 that can significantly reduce the defects of (1100, 1100', 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.

100': Pixel CSP
900: carrier substrate
1100, 1100', 1100'': Display panel

Claims (13)

Forming a plurality of RGB pixels on a wafer;
Dicing the wafer on which the plurality of RGB pixels are formed for each of the RGB pixels;
A first transfer step of transferring a pixel CSP array including a plurality of diced RGB pixels to a carrier substrate; And
A secondary transfer step of selectively transferring some of the pixel CSPs from the pixel CSP array transferred to the carrier substrate to a display panel;
Including,
The secondary transfer step,
Applying a solder paste on the plurality of pads of the display panel;
Soldering a pad of some of the pixel CSPs transferred to the carrier substrate by contacting the applied solder paste; And
Separating the carrier substrate and the remaining pixel CSP transferred to the carrier substrate from the display panel; Including,
The partial pixel CSP is selectively transferred to the display panel by using a difference between the adhesive force between the carrier substrate and the partial pixel CSP and the soldering adhesive force between the partial pixel CSP and the solder paste,
In the secondary transfer step, a pitch between two adjacent pad groups among a plurality of pad groups included in the display panel is greater than a pitch between two adjacent pixels CSP in the pixel CSP array transferred to the carrier substrate,
The carrier substrate has a predetermined ductility and is a material that can be bent by an external force,
The carrier substrate is a transparent material,
Method of manufacturing a display device.
The method of claim 1,
The step of forming the plurality of RGB pixels,
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; including, a method of manufacturing a display device.
The method of claim 1,
The step of forming the plurality of RGB pixels,
Growing a plurality of epits 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 a plurality of openings positioned on the plurality of epits in the blocking dam;
Forming a color conversion layer in at least a portion of the plurality of openings; And
Forming an encapsulation layer on the blocking dam on which the color conversion layer is formed; including, a method of manufacturing a display device.
delete delete delete delete delete The method of claim 1,
The display panel is a large-area display panel,
To prepare one carrier substrate manufactured by the first transfer step,
By repeatedly performing the secondary transfer step, some of the pixel CSPs of the pixel CSP array transferred to the one carrier substrate are transferred to the first part of the large-area display panel, and the remaining pixel CSPs are displayed in the large-area display panel. A method of manufacturing a display device, which is transferred to a second part different from the first part of the panel.
Forming a plurality of RGB pixels on a wafer, and dicing for each of the RGB pixels;
A first transfer step of transferring a pixel CSP array including a plurality of diced RGB pixels to a first transfer medium having a first adhesive force; And
A secondary transfer step of selectively transferring the pixel CSP array transferred to the first transfer medium to a second transfer medium having a second adhesive force greater than the first adhesive force applied to the display panel; and
The secondary transfer step,
Applying the second transfer medium on a plurality of pads of the display panel;
Soldering the pads of some of the pixel CSPs transferred to the first transfer medium to the applied second transfer medium; And
Separating the first transfer medium and the remaining pixel CSP transferred to the first transfer medium from the display panel; including,
In the secondary transfer step, a pitch between two adjacent pad groups among a plurality of pad groups included in the display panel is greater than a pitch between two adjacent pixels CSP in the pixel CSP array transferred to the first transfer medium. Big,
The first transfer medium is a material that has a predetermined ductility and can be bent by an external force,
The first transfer medium is a transparent material,
Method of manufacturing a display device. delete delete delete

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