KR20210015033A - Method for manufacturing display apparatus using extension and shift region of electrode pad and display apparatus manufactured by that method - Google Patents

Abstract

The present invention relates to a method for manufacturing a display device and a display device manufactured thereby, and more particularly, to a method for manufacturing a display device through transfer between an extended electrode pad of a pixel CSP and an electrode pad moved in a region of a display panel. According to an embodiment of the present invention, the method for manufacturing a display device through expansion and region movement of an electrode pad, comprises: a pixel CSP array forming step of forming a pixel CSP array in a transfer frame by forming a pixel CSP including a plurality of light emitting devices at a plurality of openings arranged in an array form in the transfer frame; an electrode region moving step of widening an electrode interval by horizontally moving a pair of opposite electrodes of a display panel in a region; a first transfer step of transferring the pixel CSP array from the transfer frame to a carrier substrate; and a second transfer step of transferring the pixel CSP array transferred to the carrier substrate to the display panel.

Description

TECHNICAL FIELD The manufacturing method of a display device through the expansion of electrode pads and movement of the area, and a display device manufactured by the method.

The present invention relates to a method of manufacturing a display device and a display device manufactured by the method, and more particularly, a method of manufacturing a display device through transfer between an extended electrode pad of a pixel CSP and an electrode pad moved to an area of the display panel. And to a display device manufactured by the method.

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.

Therefore, there is a problem that a simple pick & place method takes a long time to make a 40-inch display device, so there is a situation in which methods of transferring a large number of light emitting diodes within a short amount of time are being developed. .

In general, the micro LED refers to an LED having a size of 30 µm * 30 µm to 100 µm * 100 µm, and is applied to a backlight light source, a display light source, and a display device.

In order to apply micro LEDs as display pixels, it is necessary to transfer and integrate red, green, and blue micro LED element arrays at high speed to a target substrate for display.

Transferring to a display target substrate using micro LEDs requires transferring a large amount of micro LED chips of the order of tens to millions of units at high speed, so a corresponding technology is required.

In the micro LED chip transfer technology described above, two problems arise in electrical connection of a micro LED having a size of about 100 μm or less. The first is an electrical open defect caused by the small size of the electrode pads of the micro LED, and the second is an electrical short defect caused by a narrow distance between the electrode pads of the display target substrate.

From the perspective of the first micro LED electrode pad, Korean Patent Registration No. 10-1993863 introduces the concept of extending the electrode pad of the LED chip as a method for transferring the micro-unit LED chip, and discloses an LED integrated module having an extended electrode pad. Are doing.

However, the electrode pad was expanded to facilitate the subsequent process, but by forming the electrode pad portion extended to a distance of 3 to 5 times the size of the area where the LED chip was formed, the LED chip in micro units was substantially It has a problem of expanding to size.

In addition, since the micro-unit LED chip is substantially enlarged to the size of the millimeter unit, the pitch between individual LED chips increases when transferred to the display target substrate, resulting in a decrease in resolution.

In addition, an extended electrode electrode pad portion is formed in a second area separated by a predetermined distance from the first area in which the electrode of the LED chip is formed, so that the LED chip electrode located in the first area and the extended electrode pad portion formed in the second area are electrically Since it is a structure in which 6 wires must be connected for connection, it is not suitable for a micro-unit LED chip, and since 6 wires are added to one LED chip, very many wires are added when tens to millions of microchips are arrayed. Therefore, there is a limit to the structure in which the problems of disconnection or defects can only be exposed.

Second, along with the expansion of the electrode pad of the LED chip in the micro unit, the problem of expansion of the electrode of the target substrate of the display device to be transferred also arises.

In the case of a micro LED chip, since the chip size is smaller than 100 μm, the spacing between the electrode pads of the chip is very narrow, such as 50 μm or less. The display device target substrate has electrode pads with the same narrow spacing as the chip because it corresponds one-to-one with the chip electrode pad. In addition, between the (+) (-) electrode pads of the target substrate may have a well shape. Accordingly, there is a problem that solder paste is trapped between the narrow and well-shaped (+) (-) electrode pads, resulting in an electrical short between both electrodes.

Korean Patent Registration 10-1993863 Republic of Korea Patent Publication 10-2018-0075310

The problem to be solved according to the configuration of the present invention is to solve the electrical connection problem (open, sorting failure) that occurs in the conventional surface mounting process of a chip unit when configuring a display or device, the present invention is a pad extended pixel It is intended to scale up the electrical connection process of micro LEDs in the area of several tens µm to the electrical connection process of pixel CSPs in the area of several hundred µm by simultaneously introducing the CSP and the region-moved electrode pad (target substrate).

An object of the present invention is to provide a method and apparatus capable of rapidly manufacturing a large-area display device by preventing an open/short defect between electrodes in a transfer process constituting a display device through the above-described scale-up and securing an alignment margin.

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.

According to an embodiment of the present invention, a method of manufacturing a display device through expansion of an electrode pad and movement of an area is provided by forming a pixel CSP including a plurality of light emitting elements in each of a plurality of openings arranged in an array in a transfer frame. Forming a pixel CSP array in the pixel CSP array; An electrode region moving step of increasing an electrode gap by moving a pair of electrodes facing each other on the display panel to the left and right; A primary transfer step of transferring the pixel CSP array from the transfer frame to a carrier substrate; And a second transfer step of transferring the pixel CSP array transferred to the carrier substrate to the display panel.

Here, after the step of forming the pixel CSP array, an extended metal deposition step of depositing a metal into an extended area from the electrode pad by attaching a shadow mask to the frame surface of the electrode pad side of the pixel CSP. I can.

Here, a shadow mask removing step of removing the shadow mask; A frame removing step of removing the frame; And attaching a protective film to the frame surface on the opposite side on which the shadow mask is disposed before the extended metal deposition step, a protective film attaching step.

Here, the step of forming the pixel CSP array includes: arranging a substrate under the transfer frame to close the lower openings of each of the plurality of openings; A light emitting device forming step of disposing the plurality of light emitting devices on the substrate in the plurality of openings; Filling and curing a protective layer encapsulating the plurality of light emitting devices in the plurality of openings, forming a protective layer; And removing the substrate, removing the substrate.

Here, the distance between the plurality of openings of the transfer frame may be the same as the distance between the pixel CSP arrays of the target substrate to be transferred.

Here, the first transfer step may include: attaching the carrier substrate to the transfer frame and the pixel CSP array; And separating the pixel CSP array from the plurality of openings of the transfer frame while the pixel CSP array is attached to the carrier substrate by removing the carrier substrate from the transfer frame.

Here, the secondary transfer step may include applying a solder paste on a plurality of pads of the display panel; A soldering step of contacting and soldering the pads of the pixel CSP array transferred to the carrier substrate to the applied solder paste; And separating the carrier substrate from the pixel CSP array, separating the carrier substrate.

Here, each of the plurality of pixel CSPs is separated by a protective layer, the first transfer step has a first adhesive force between the transfer frame and the protective layer, and transfers the pixel CSP array from the first transfer frame. Transferring to a carrier substrate having a second adhesive force greater than the first adhesive force, and in the second transfer step, from the carrier substrate by a solder paste having a third adhesive force greater than the second adhesive force applied to the display panel substrate. The pixel CSP array may be transferred to the display panel substrate.

In addition, the display device according to the exemplary embodiment of the present invention may be manufactured by the method of manufacturing a display device by extending the electrode pad and moving the region.

Using the method of manufacturing a display device according to the embodiment, by simultaneously introducing a pad-extended pixel CSP and a region-moved electrode pad (target substrate), and performing a surface mounting process of the display panel, micro LED electrical in a tens µm area Defects such as electrical open/short can be minimized by scaling up the connection process to a pixel CSP electrical connection process in a region of several hundred μm.

In addition, it is possible to provide a method and apparatus for quickly manufacturing a large-area display device by preventing electrical open/short defects in the transfer process constituting the display device through scale-up and increasing alignment margin. have.

1A to 1C are diagrams for explaining a transfer frame used in a method of manufacturing a pixel CSP having an extended electrode pad according to an embodiment of the present invention.
2 to 4 are diagrams for explaining in detail a step of forming a pixel CSP array in a transfer frame.
5 are diagrams for explaining in detail a step of extending an electrode pad in each pixel CSP in a pixel CSP array formed in a transfer frame.
6 is a side view and a plan view of a pixel CSP including an extended electrode pad.
7 is a view showing a comparison before and after movement of an electrode pad of a display panel.
FIG. 8 is a diagram illustrating an electrical contact structure between an extended electrode pad of a pixel CSP and an electrode pad moved by a region of a display panel according to an exemplary embodiment of the present invention.
9 is a view for explaining in detail a step of transferring a pixel CSP array formed on a transfer frame to a carrier substrate.
10 is a diagram showing a structure of an electrode pad of a display panel.
FIG. 11 is a diagram for describing in detail a step of transferring a pixel CSP array transferred to a carrier substrate to a display panel based on the cross section AA of FIG. 10.
12 is a view for explaining in detail a step of transferring the pixel CSP array transferred to the carrier substrate to the display panel based on the cross section BB of FIG. 10.
FIG. 13 is a plan view showing that a plurality of protective layers encapsulating one pixel CSP shown in FIG. 11C are transferred to a display panel along a plurality of row and column directions.

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.

The display device according to an embodiment of the present invention includes the steps of forming a pixel CSP array on a transfer frame, primary transfer of the pixel CSP array formed on the transfer frame to a carrier substrate, and a pixel CSP transferred to the carrier substrate. It may consist of a step of secondary transfer of the array to the display panel.

Here, in the step of forming the pixel CSP array prior to the primary transfer of the pixel CSP array to the carrier substrate, the electrode pads of the pixel CSP are extended to form the expandable electrode pad portion, and the CSP is manufactured and transferred to the display panel. It provides a pixel CSP having an extended electrode pad that can manufacture large-area display devices by preventing open defects and increasing alignment margins.

1A to 1C are views for explaining a transfer frame used in a method of manufacturing a pixel CSP having an extended electrode pad according to an embodiment of the present invention, and FIG. 1A is a transfer frame ( 200) is a perspective view, FIG. 1(b) is a partially enlarged plan view in FIG. 1(a), and FIG. 1(c) is a cross-sectional view of FIG. 1(b).

1A to 1C, the transfer frame 100 has a plate shape and includes an upper surface and a lower surface, and a plurality of side surfaces.

The transfer frame 100 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 100 has a flat plate shape, the transfer frame 100 may be referred to as a horizontal frame.

The transfer frame 100 has a plurality of openings 110.

Each of the openings 110 is formed to penetrate the upper and lower surfaces of the transfer frame 100, and the plurality of openings 110 may be arranged in an array form in the transfer frame 100 in a plurality of row and column directions.

The picth between the plurality of openings 110 may be the same as the spacing of the pixel CSP array formed on the display panel according to manufacturing of the display device in the future.

The size of the opening 110 of the transfer frame 100 may correspond to the size of the pixel CSP.

For example, the width (W) * length (h) * thickness (t) of the opening 110 of the transfer frame 100 may be 30 * 30 * 10 (μm) ~ 1000 * 1000 * 500 (μm). .

The upper opening and the lower opening of the opening 110 of the transfer frame 100 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 110 of the transfer frame 100 may be a hexahedral empty space, but is not limited thereto, and the shape of the opening 110 may be a cylindrical empty space or an oval-cylindrical empty space. It may be a space, an empty space in the shape of a polygonal cylinder, or an empty space in the shape of a polyhedron.

The material of the transfer frame 100 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 100 may be 10 (μm) to 500 (μm).

2 to 4 are diagrams for explaining in detail a step of forming a pixel CSP array in a transfer frame.

2A is a schematic cross-sectional view of any one of the plurality of openings 110 of the transfer frame 100 shown in FIG. 1.

Referring to FIG. 2A, a substrate 200 is formed on one of the upper and lower surfaces of the transfer frame 100 (lower surface in FIG. 2 ).

As the substrate 200 is formed under the transfer frame 100, the lower opening of the opening 110 is blocked by the substrate 200.

A space in which the pixel CSP can be formed may be provided by the opening 110 and the substrate 200.

Next, referring to FIG. 2B, a plurality of light emitting devices 300R, 300G, and 300B are disposed on the substrate 200 inside the opening 110.

Here, the electrode pads of each of the plurality of light emitting devices 300R, 300G, and 300B may be disposed to contact the upper surface of the substrate 200.

The plurality of light-emitting devices 300R, 300G, and 300B may include a first light-emitting device 300R, a second light-emitting device 300G, and a third light-emitting device 300B.

The first light emitting device 300R may be a red light emitting chip that emits red light, the second light emitting device 300G may be a green light emitting chip that emits green light, and the third light emitting device 300B emits blue light It may be a blue light emitting chip.

Each light-emitting device (300R, 300G, 300B) may have a flip-chip structure that does not require a wire, and each light-emitting device (300R, 300G, 300B) may emit light of a specific wavelength, or the fluorescent light contained therein Light of a specific wavelength may be emitted by a material or quantum dot.

In addition, each of the light emitting devices 300R, 300G, and 300B 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.

Also, when the chip area is 80% or more of the package area, it is called CSP. When each of the light-emitting elements 300R, 300G, and 300B is a CSP, it may be composed of a flip chip emitting light of a specific wavelength and a phosphor covering the flip chip.

Light emitted from the flip chip excites the phosphor, so that light of a specific wavelength may be emitted.

A plurality of light emitting devices 300R, 300G, and 300B disposed in the opening 110 may be included in one pixel CSP 300.

One pixel CSP 300 may function as one pixel that emits various colors from the display panel.

Next, referring to FIG. 2C, the protective layer 400 is filled in the opening 110 and the protective layer 400 is cured.

The protective layer 400 may be an electrically insulating material. For example, it may be a transparent material such as silicone, epoxy, resin, or polymer.

One pixel CSP 300 may include a passivation layer 400.

That is, one pixel CSP 300 may include a plurality of light emitting devices 300R, 300G, and 300B and a protective layer 400 encapsulating the plurality of light emitting devices 300R, 300G, and 300B.

The shape of the cured protective layer 400 or the shape of one pixel CSP 300 corresponds to the shape of the opening 110 of the transfer frame 100.

Accordingly, the shape of the protective layer 400 or the shape of one pixel CSP 300 may vary according to the shape of the opening 110 of the transfer frame 100.

The shape of the opening 110 of the transfer frame 100 can be understood from the shape of the protective layer 400 or the shape of one pixel CSP 300, and through this, a pixel having an expandable electrode pad according to an embodiment of the present invention The manufacturing method of CSP can be estimated.

Next, referring to FIG. 2D, when the protective layer 400 is cured, the substrate 200 is separated from the transfer frame 100 and the protective layer 400.

When the substrate 200 is separated, a plurality of electrode pads 310R, 310G, and 310B of the pixel CSP 300 may be exposed to the outside.

The plurality of electrode pads 310R, 310G, 310B may vary depending on the number of light emitting elements included in one pixel CSP 300, for example, the number of light emitting elements included in one pixel CSP 300 If is 3, since 2 electrode pads are required for each light emitting element, a total of 6 electrode pads can be formed, or when the (+) electrode is a common electrode, a total of 4 electrode pads can be formed.

After forming the pixel CSP 300 in each of the plurality of openings 110 of the transfer frame 100, and filling and curing the protective layer 400 for each of the plurality of openings 110, it is shown in Fig. 2(D). As described above, when the substrate 200 is removed from the transfer frame 100, a plurality of light emitting devices 300R, 300G, 300B, and the protective layer 400, a plurality of the transfer frame 100 A pixel CSP array including a plurality of pixel CSPs 300 may be formed in the opening 110.

FIG. 4 is a part of the three pixel CSPs 300P1, 300P2, and 300P3 including the protective layers 400P1, 400P2, and 400P3 encapsulating the three light-emitting devices shown in FIG. 3 and a portion of the transfer frame 100 This is a cross-sectional view.

4, the first pixel CSP (300P1) is encapsulated in the first opening of the transfer frame 100 by the first protective layer (400P1), the second pixel CSP (300P2) is a second protection The layer 400P2 is encapsulated in the second opening of the transfer frame 100, and the third pixel CSP 300P3 is inserted into the third opening of the transfer frame 100 by the third protective layer 400P3. It is encapsulated.

Encapsulation exposes the electrode pad of each pixel CSP, firmly supports the LED light source module, can have a high Young's Modulus, and contains a material having high thermal conductivity to effectively dissipate heat from the LED cells. can do.

For example, the encapsulation may be an epoxy resin or a silicone resin, and may include light reflective particles for reflecting light.

5 are diagrams for explaining in detail a step of extending an electrode pad in each pixel CSP in a pixel CSP array formed in a transfer frame.

Referring to FIG. 5A, in a state in which the electrode pads 310R, 310G, and 310B are exposed as shown in FIG. 2D based on one pixel CSP 300, the electrode pads 310R, 310G, 310B) to form a protective film 500 on the opposite side.

The protective film 500 is disposed on the opposite side of the electrode pads 310R, 310G, and 310B of the transfer frame 100 shown in FIG. 3, and may be attached to protect the pixel CSP during a metal deposition process using a shadow mask. .

The protective film 500 is made of a resin film, and is not particularly limited, and the range of the adhesive force of the protective film 500 may vary depending on the characteristics of the substrate to be protected or the thickness of the substrate, so that the range of the adhesive force is varied. And can be variable.

Referring to FIG. 5B, in the state in which the protective film 500 is formed as shown in FIG. 5A, the electrode pads exposed for metal deposition for expansion of the electrode pads 310R, 310G, and 310B ( 310R, 310G, 310B) on the shadow mask (600, Shadow Mask) is placed.

The shadow mask 600 may have an exposed pattern shape in a portion A requiring metal deposition to form an extended electrode pad.

Referring to FIG. 5C, a state in which metal deposition is performed in a state in which the shadow mask 600 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, and Ti/Al may be used. In the case of three layers, various combinations of Ti/Cr/Au and Ti/Al/Au may be used.

The extended electrode pads 320R, 320G, and 320B may be formed as upper surfaces of each of the electrode pads 310R, 310G, and 310B by metal deposition through the opened portion of the shadow mask 600.

In this state, as shown in (D) of FIG. 5, when the shadow mask 600 is removed, the extended electrode pad 320R having an extended area from the electrode pads 310R, 310G, and 310B respectively formed in the RGB of the existing pixel CSP. , 320G, 320B) may be formed.

The extended area refers to a restricted area that can be extended within one pixel CSP, and is an area extending from the electrode pads 310R, 310G, 310B of each of the light-emitting elements 300R, 300G, and 300B. It means an area that does not intersect with each other.

When the protective film 500 is removed from the pixel CSP 300 in the process of FIG. 5D, the electrode pads of the plurality of pixels CSP 300 arranged in a matrix, especially the plurality of light emitting devices 300R, 300G, 300B From (310R, 310G, 310B), an array of pixel CSPs 300 having extended electrode pads 320R, 320G, and 320B having an enlarged size and one pixel CSP 300 may be obtained.

The array of pixel CSPs 300 having the extended electrode pads 320R, 320G, and 320B and each of the pixel CSPs 300 may be transferred to a display panel to implement a large display device.

6 is a side view and a plan view of a pixel CSP including an extended electrode pad.

6A is a side cross-sectional view, and (B) is a view showing a plan view as an example.

As shown, it can be seen that the electrode pads 310R, 310G, and 310B of the light-emitting elements 300R, 300G, and 300B are extended to the extended electrode pads 320R, 320G, and 320B from the side or plane It means that the surface area is expanded by that amount, and that the connection cross-sectional area between electrodes can be increased as the electrode surface area is increased.

The electrode pads 310R, 310G, 310B and the extended electrode pads 320R, 320G, and 320B refer to the first electrode, and the electrode pads 310R'. 310G'. 310B' and the extended electrode pads 320R'. 320G' , 320B') means a second electrode.

The extended electrode pads 320R, 320G, and 320B are electrode pads 310R, 310G, and 310B formed on the light-emitting elements 300R, 300G, and 300B by utilizing an existing redundant area that has not been used within one pixel CSP 300 area. ), the cross-sectional area can be enlarged.

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 electrode pads are also very fine. Occurs and 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 the alignment margin between the pixel CSP pad and the display panel pad during the surface mounting process on the display device, and to quickly manufacture a large-area display device.

7 is a view showing a comparison before and after movement of an electrode pad of a display panel, and FIG. 8 is a view showing an electrical contact structure between an extended electrode pad of a pixel CSP and an electrode pad that has been moved by an area of the display panel according to an embodiment of the present invention. It is a drawing.

7 shows an electrode pad array of a display panel, which may have an arrangement corresponding to the light emitting elements 300R, 300G, and 300B of one pixel CSP 300P1 of the LED.

7(A1), (B1), and (C1) are layout diagrams of electrode pads on a conventional display panel, and (A2), (B2), and (C2) are diagrams on a display panel according to an embodiment of the present invention. This is an example of electrode pad arrangement.

In the case of micro-unit LEDs, since the size of the LED is less than 100㎛*100㎛, the distance d1 between the electrode pads of the display panel corresponding thereto is also very narrow, so in the present invention, the distance between the electrode pads of the display panel (d2) is widened. Thus, it is possible to prevent a short circuit due to solder paste between electrode pads in advance.

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

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

The present invention proposes a first transfer and a second transfer to be described in the following FIGS. 9 to 15 as a method for simultaneously transferring a plurality of pixel CSPs 300 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 800 and the solder paste 740 is adopted.

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

If the distance between the electrode 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 electrode pads 72 and 72' A step is formed between the electrode pads 72 and 72 ′ not filled with the ink 73, and the solder paste 74 is trapped, so that a short circuit may occur due to the remaining solder paste.

Accordingly, in order to solve the above problem, the present invention moves the electrode pads 720 and 720 ′ of the display panel 700 left and right to increase the distance d2 between the electrode pads 720 and 720 ′. The white ink dam can be formed by the ink 730. That is, the gap between the electrode pads 720 and 720 ′ is widened, so that white ink may be filled between the electrode pads.

With the formation of the white ink dam, a step difference between the electrode 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 electrode 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 between the electrode pads 720 and 720 ′ of the display panel 700 is that the electrode pads 310P1, 310P2 and 310P3 of the pixel CSP 300 are extended as in FIGS. 5 and 6 described above. It is possible by the extended electrode pads 320P1, 320P2, and 320P3.

8, the extended electrode pads 320P1, 320P2, and 320P3 of the pixel CSP 300 are shown, and the electrode pads 720 and 720' of the display panel 700 are spaced d2 due to the extended electrode pads. Even if it is widened to, matching between electrodes is sufficiently possible.

As a result, the area movement of the extended electrode pads 320P1, 320P2, and 320P3 of the pixel CSP 300 and the electrode pads 720 and 720' of the display panel 700 is performed by the first transfer to be described in FIGS. 9 to 15. And when the second transfer is performed, the work area is scaled up from micro to millimeter, so that the transfer process can be accelerated and tens of thousands to hundreds of thousands of pixel CSPs can be simultaneously transferred.

Next, a method of transferring the pixel CSP array formed on the substrate to the display panel through primary transfer and secondary transfer will be described.

9 is a view for explaining in detail a step of transferring a pixel CSP array formed on a transfer frame to a carrier substrate.

The transfer frame 100 may be referred to as a first transfer medium in the 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.

The step of transferring the pixel CSP array formed on the transfer frame to the carrier substrate may be referred to as “primary transfer”.

(A) of FIG. 9 is one of the three pixel CSPs 300P1, 300P2, and 300P3 including the protective layers 400P1, 400P2, and 400P3 encapsulating the three light-emitting elements in FIG. 3 and the transfer frame 100 It is a cross-sectional view of the part.

Referring to FIG. 9A, the first pixel CSP 300P1 is encapsulated in the first opening of the transfer frame 100 by the first protective layer 400P1, and the second pixel CSP 300P2 Is encapsulated in the second opening of the transfer frame 100 by the second protective layer 400P2, and the third pixel CSP 300P3 is the third pixel of the transfer frame 100 by the third protective layer 400P3. It is encapsulated in 3 openings.

Next, referring to FIG. 9B, the carrier substrate 800 is attached to the upper surface of the transfer frame 100 and the upper surfaces of the first to third protective layers 400P1, 400P2 and 400P3.

Here, the carrier substrate 800 is for extracting the corresponding protective layers 400P1, 400P2, 400P3 encapsulating each pixel CSP (300P1, 300P2, 300P3) from the plurality of openings 110 of the transfer frame 100 will be.

Here, the carrier substrate 800 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. 9C, the transfer frame 100 is removed. If the adhesive force between the carrier substrate 800 and each protective layer (400P1, 400P2, 400P3) is greater than the adhesive force between the transfer frame 100 and each protective layer (400P1, 400P2, 400P3), only the transfer frame 100 is carrier It can be removed from the substrate 800 and the plurality of protective layers 400P1, 400P2, 400P3.

Therefore, it is preferable that the carrier substrate 800 has an adhesive force greater than that between the transfer frame 100 and each of the protective layers 400P1, 400P2, and 400P3.

Meanwhile, the carrier substrate 800 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.

FIG. 10 is a view showing the electrode pad structure of the display panel, and FIG. 11 is a view for explaining in detail a step of transferring the pixel CSP array transferred to the carrier substrate to the display panel based on the AA cross section of FIG. 10, FIG. 12 is a diagram for explaining in detail a step of transferring the pixel CSP array transferred to the carrier substrate to the display panel based on the cross section BB of FIG. 10, and FIG. 13 is A plan view showing a plurality of protective layers encapsulating a pixel CSP are transferred to a display panel along a plurality of row and column directions.

Referring to FIG. 10, (A) is an enlarged plan view of a portion of the display panel 700, (B) is an A-A cross-sectional view of (A), and (C) is a B-B cross-sectional view of (A).

Referring to FIG. 10, the display panel 700 includes a plurality of electrode pads 720 electrically connected to each of the pads 310P1, 310P2, 310P3 of the plurality of pixel CSPs shown in FIG. 9C. .

A plurality of electrode pads 720 may be arranged on the upper surface of the display panel 700. The plurality of electrode pads 720 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 110 of the transfer frame 100 shown in FIG. 1.

Next, referring to FIGS. 11A and 12A, a solder paste 740 is applied on the plurality of electrode pads 720 of the display panel 700. The solder paste 740 may be applied on the plurality of electrode pads 720 of the display panel 700 through various methods such as screen printing, dispensing, and jetting.

Next, referring to FIGS. 11B and 12B, the pixel CSP 300P1 is attached to the carrier substrate 800 and the carrier substrate 800 manufactured in FIG. 9C, and therein, A plurality of protective layers (400P1, 400P2, 400P3) having 300P2, 300P3) are moved onto the display panel 700, and the electrode pads 310P1, 310P2, 310P3 of each pixel CSP (300P1, 300P2, 300P3) are displayed. The solder paste 740 applied on the electrode pads 720P1, 720P2, and 720P3 of the panel 700 is brought into contact.

After the pads 310P1, 310P2, 310P3 of the pixel CSPs 300P1, 300P2, 300P3 and the electrode pads 720P1, 720P2, 720P3 of the display panel 700 are in contact with each other through the solder paste 740, for example, When a predetermined heat is applied using a self-aligning paste (SAP) soldering method, the solder particles contained in the solder paste 740 become the pads 310P1 of the pixel CSPs (300P1, 300P2, 300P3). , 310P2, 310P3 and the electrode pads 720P1, 720P2, 720P3 of the display panel 700 may be self-assembled (self-assembly).

Meanwhile, the thermosetting resin included in the solder paste 740 may be cured by heat.

Next, referring to FIGS. 11C and 12C, the pads 310P1, 310P2, 310P3 of the pixel CSPs 300P1, 300P2, 300P3 and the electrode pads 720P1 of the display panel 700, When the 720P2 and 720P3 are soldered, the carrier substrate 800 is removed from the plurality of protective layers 400P1, 400P2 and 400P3.

Here, the soldering adhesion between the pads 310P1, 310P2, 310P3 of the pixel CSP (300P1, 300P2, 300P3) and the electrode pads 720P1, 720P2, 720P3 of the display panel 700 is determined by the carrier substrate 800 and each protective layer. Since it is much larger than the adhesion between (400P1, 400P2, 400P3), only the carrier substrate 800 can be easily separated.

Referring to FIG. 12, first and second electrode pads 310R and 310R' of one light emitting device 300R in pixel CSPs 300P1, 300P2, and 300P3 as in FIGS. 7 and 8, and the first and It is possible to widely adjust the spacing between the electrode pads 720 and 720 ′ of the display panel 700 by the extended electrode pads 320R and 320R ′ formed on the second electrode pads 310R and 310R′, that is, the electrode pads Area movement of (720, 720') is possible.

That is, it is possible to improve the contact margin between the pixels CSP (300P1, 300P2, 300P3) and the display panel 700 during the transfer process by the extended electrode pads 320R, 320R', and the electrode of the display panel 700 The pads 720 and 720' can be moved in the same area as both sides of the pads 720 and 720' are wide open, 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.

13 illustrates a plurality of protective layers 400P1, 400P2, 400P3 encapsulating one pixel CSP shown in FIGS. 11C and 12C in a plurality of rows on the display panel 700 It is a plan view showing the transfer along the overheating direction.

Meanwhile, the solder paste 740 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 110 of the transfer frame 100 illustrated in FIG. 1 and the number of pixel CSPs 300 formed in the display panel 700 illustrated in FIG. 13 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 100 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.

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 construed 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: transcription frame
200: substrate
300: Pixel CSP
400: protective layer
500: protective film
600: shadow mask
700: display panel
800: carrier substrate

Claims (9)

Forming a pixel CSP array in the transfer frame by forming a pixel CSP including a plurality of light emitting elements in each of a plurality of openings arranged in an array form in the transfer frame to form a pixel CSP array in the transfer frame;
An electrode region moving step of increasing an electrode gap by moving a pair of electrodes facing each other on the display panel to the left and right;
A primary transfer step of transferring the pixel CSP array from the transfer frame to a carrier substrate; And
A second transfer step of transferring the pixel CSP array transferred to the carrier substrate to the display panel, comprising: a method of manufacturing a display device through expansion of an electrode pad and movement of an area. The method of claim 1,
After the step of forming the pixel CSP array, an extended metal deposition step of depositing a metal in an extended area from the electrode pad by attaching a shadow mask to the frame surface on the electrode pad side of the pixel CSP. A method of manufacturing a display device by extending a pad and moving an area. The method of claim 2,
A shadow mask removing step of removing the shadow mask;
A frame removing step of removing the frame; And
A method of manufacturing a display device by extending an electrode pad and moving an area, further comprising: attaching a protective film to the surface of the frame on the opposite side where the shadow mask is disposed before the extended metal deposition step. The method of claim 1,
The step of forming the pixel CSP array,
Placing a substrate under the transfer frame to close the lower openings of each of the plurality of openings;
Forming a light emitting device, disposing the plurality of light emitting devices on the substrate in the plurality of openings;
Filling and curing a protective layer encapsulating the plurality of light emitting devices in the plurality of openings, forming a protective layer; And
A method of manufacturing a display device by extending the electrode pad and moving the region, including; removing the substrate from the substrate. The method of claim 1,
A method of manufacturing a display device by extending an electrode pad and moving an area, wherein the distance between the plurality of openings of the transfer frame is the same as the distance between the pixel CSP arrays of the target substrate to be transferred. The method of claim 1,
The first transfer step,
Attaching the carrier substrate to the transfer frame and the pixel CSP array; And
A step of separating the pixel CSP array from the plurality of openings of the transfer frame while the pixel CSP array is attached to the carrier substrate by removing the carrier substrate from the transfer frame; including, expansion and region of the electrode pad A method of manufacturing a display device through movement. The method of claim 1,
The secondary transfer step,
Applying a solder paste on a plurality of pads of the display panel;
A soldering step of contacting and soldering the pads of the pixel CSP array transferred to the carrier substrate to the applied solder paste; And
Separating the carrier substrate from the pixel CSP array, separating the carrier substrate; comprising, a method of manufacturing a display device through the expansion and area movement of the electrode pad. The method of claim 1,
Each of the plurality of pixel CSPs is separated by a protective layer,
The first transfer step has a first adhesive force between the transfer frame and the protective layer, and transfers the pixel CSP array from the first transfer frame to a carrier substrate having a second adhesive force greater than the first adhesive force,
The second transfer step may include transferring the pixel CSP array from the carrier substrate to the display panel substrate by using a solder paste having a third adhesive force greater than the second adhesive force applied to the display panel substrate. And a method of manufacturing a display device through area movement. A display device manufactured by the method of manufacturing a display device by expanding the electrode pad and moving the region according to any one of claims 1 to 8.

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