JP2022177487A - Display device manufacturing method - Google Patents

Abstract

To improve yield in separating an LED chip and a semiconductor substrate from each other by using laser irradiation.SOLUTION: A method for manufacturing a display includes: preparing a first substrate having a plurality of LED chips that are arranged in M columns×N rows (M, N are an integer of 1 or more); bonding the first substrate to a second substrate with the plurality of LED chips therebetween; selectively irradiating a first group of LED chips of the plurality of LED chips with a laser beam to separate the first group of LED chips from the first substrate; and selectively irradiating a second group of LED chips of the plurality of LED chips with a laser beam to separate the second group of LED chips from the first substrate. When the positions of the first group of LED chips are represented by (Mx, Ny), the positions of the second group of LED chips are represented by (Mx±1, Ny) or (Mx, Ny±1).SELECTED DRAWING: Figure 1

Description

One embodiment of the present invention relates to a method of manufacturing a display device. In particular, the present invention relates to a method of manufacturing a display device mounted with an LED (Light Emitting Diode) chip.

2. Description of the Related Art In recent years, as a next-generation display device, an LED display in which each pixel is mounted with a minute LED chip has been developed. An LED display has a structure in which a plurality of LED chips are mounted on a circuit board forming a pixel array. The circuit board has a drive circuit for causing the LED to emit light at a position corresponding to each pixel. These drive circuits are electrically connected to each LED chip, respectively.

There are various methods for mounting a plurality of LED chips on a circuit board. For example, a method is known in which only the support substrate is removed after the LED chips provided on the support substrate are adhered to the circuit board. For example, Patent Literature 1 describes a technique of separating an LED chip from a supporting substrate by using a method called laser lift-off (LLO) after bonding the LED chip on a circuit board.

U.S. Patent No. 10096740

One of the objects of the present invention is to improve the yield when separating an LED chip and a semiconductor substrate using laser irradiation.

A method for manufacturing a display device according to an embodiment of the present invention includes preparing a first substrate having a plurality of LED chips arranged in M rows×N columns (M and N are integers of 1 or more), By bonding the first substrate to the second substrate through the LED chips and selectively irradiating the LED chips in the first group among the plurality of LED chips with laser light, the LED chips in the first group is separated from the first substrate, and the LED chips of the second group are separated from the first substrate by selectively irradiating the LED chips of the second group among the plurality of LED chips with laser light. When each position of the LED chips in the first group is represented by (M _x , N _y ), each position of the LED chips in the second group is (M _x±1 , N _y ) or (M _x , N _y±1 ).

It is a flowchart figure which shows the manufacturing method of the display apparatus in 1st Embodiment. 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; FIG. 4 is a plan view for explaining the arrangement of a first group of LEDs and a second group of LEDs in the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; FIG. 4 is a plan view showing a state of the LED chip adhered to the carrier substrate in the manufacturing method of the display device according to the first embodiment; FIG. 4 is a plan view showing a state of an LED chip adhered to a carrier substrate in a method of manufacturing a display device in a comparative example; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 4A to 4C are cross-sectional views showing the method of manufacturing the display device according to the first embodiment; 1 is a plan view showing a schematic configuration of a display device according to a first embodiment; FIG. 2 is a block diagram showing the circuit configuration of the display device according to the first embodiment; FIG. 2 is a circuit diagram showing the configuration of a pixel circuit of the display device according to the first embodiment; FIG. 2 is a cross-sectional view showing the configuration of a pixel of the display device according to the first embodiment; FIG. FIG. 8 is a plan view for explaining the arrangement of the first group of LEDs, the second group of LEDs, the third group of LEDs, and the fourth group of LEDs in the second embodiment; FIG. 11 is a plan view for explaining the arrangement of the first group of LEDs and the second group of LEDs in the third embodiment; FIG. 11 is a plan view for explaining the arrangement of the first group of LEDs and the second group of LEDs in the third embodiment; It is a sectional view showing a manufacturing method of a display in a 5th embodiment. It is a sectional view showing a manufacturing method of a display in a 5th embodiment. It is a sectional view showing a manufacturing method of a display in a 5th embodiment. It is a sectional view showing a manufacturing method of a display in a 5th embodiment. It is a sectional view showing a manufacturing method of a display in a 5th embodiment. It is a sectional view showing a manufacturing method of a display in a 5th embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in various modes without departing from the gist thereof. The present invention should not be construed as being limited to the description of the embodiments exemplified below. In order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual mode. However, the drawings are merely examples and are not intended to limit the interpretation of the invention.

When describing embodiments of the present invention, the direction from the substrate toward the LED chip is defined as "up", and the opposite direction is defined as "down". However, the expressions "above" or "below" merely describe the upper limit relationship of each element. For example, the expression that an LED chip is arranged on a substrate also includes the case where another member is interposed between the substrate and the LED chip. Furthermore, the expressions “above” or “below” include not only the case where each element overlaps in plan view, but also the case where they do not overlap.

When describing the embodiments of the present invention, elements having the same functions as those already described may be denoted by the same reference numerals or the same reference numerals with symbols such as alphabets, and description thereof may be omitted. In addition, when it is necessary to distinguish a certain element for each color of RGB, it is distinguished by adding a symbol of R, G or B after the code indicating the element. However, when it is not necessary to describe the elements separately for each color of RGB, only the symbols indicating the elements will be used for description.

<First embodiment>
[Manufacturing method of display device]
FIG. 1 is a flow chart showing a method for manufacturing the display device 10 according to the first embodiment. Specifically, FIG. 1 shows a process of transferring a plurality of LED chips 202R formed on the element substrate 200 to the carrier substrate 301. FIG. 2 to 4, 6 and 7 are cross-sectional views showing the manufacturing method of the display device 10 according to the first embodiment. FIG. 5 is a plan view for explaining the arrangement of the first group of LEDs and the second group of LEDs in the first embodiment. First, the process up to transferring each LED chip 202R to the carrier substrate 301 will be described with reference to FIG. At that time, specific examples of each process will be described with reference to FIGS. 2 to 7. FIG.

First, in step S11 of FIG. 1, an element substrate 200 having a plurality of LED chips 202R arranged in M rows×N columns (M and N are integers equal to or greater than 1) is prepared (see FIG. 2). The plurality of LED chips 202R are LED chips that emit red light. The LED chip 202</b>R can be formed by growing a semiconductor layer on the semiconductor substrate 201 . A sapphire substrate, for example, can be used as the semiconductor substrate 201 . Also, as the semiconductor layer, for example, gallium nitride (GaN) can be grown. However, the LED chip 202R may be formed using a semiconductor layer (for example, an InGaAlP layer) grown on another semiconductor substrate such as a gallium arsenide (GaAs) substrate. In this case, another semiconductor substrate on which the LED chip 202R is formed may be adhered to the semiconductor substrate 201 and used.

Next, in step S12 of FIG. 1, the element substrate 200 is adhered to the carrier substrate 301 via the plurality of LED chips 202R (see FIG. 3). The carrier substrate 301 is a sheet member made of silicon or acrylic and has adhesiveness. The adhesive force of the carrier substrate 301 can be adjusted by laser light irradiation or the like. A known carrier substrate can be used as such a carrier substrate 301 .

Next, in step S13 of FIG. 1, by selectively irradiating the LED chips 202Ra of the first group among the plurality of LED chips 202R with the laser beam 40, the LED chips 202Ra of the first group are removed from the element substrate 200. Separate (see Figure 4). Specifically, as shown in FIG. 4, the semiconductor substrate 201 and the LED chip 202Ra are separated by irradiating the laser beam 40 through the light shielding mask 30 . This process is a so-called laser lift-off process.

In the process shown in FIG. 4 , only the first group of LED chips 202Ra among the plurality of LED chips 202R included in the element substrate 200 is irradiated with the laser light 40 . Specifically, the first group of LED chips 202Ra is selectively irradiated with the laser light 40 from among the plurality of LED chips 202R including the first group of LED chips 202Ra and the second group of LED chips 202Rb. .

The arrangement of the first group of LED chips 202Ra and the second group of LEDs 202Rb is as shown in FIG. As shown in FIG. 5, the first group of LED chips 202Ra and the second group of LED chips 202Rb are arranged in a staggered arrangement. That is, in each row and each column, the LED chips 202Ra of the first group and the LED chips 202Rb of the second group are alternately arranged. When divided as shown in FIG. 5, the number of LED chips 202Ra in the first group and the number of LED chips 202Rb in the second group are substantially the same. Here, "substantially the same" includes not only the case of complete matching but also the case of having an error within a range that can be regarded as being substantially the same.

Further, in accordance with the arrangement of the LED chips 202R described above, the light shielding mask 30 shown in FIG. 4 has a plurality of openings 30a arranged in a zigzag arrangement in plan view. As described above, the number of LED chips 202Ra in the first group is half of all the LED chips 202R included in the element substrate 200, so the pitch of the plurality of openings 30a is twice the pitch of the plurality of LED chips 202R. is. However, not limited to this example, when the number of LED chips to be processed is even smaller, the pitch of the plurality of openings 30a may be double or more.

As the laser beam 40, a laser beam that is not absorbed by the semiconductor substrate 201 but is absorbed by the LED chip 202Ra is selected. In this embodiment, ultraviolet light is used as the laser light 40 . As the light source of the laser beam 40, a solid laser such as YAG laser or _YVO4 laser, or an excimer laser may be used. However, for the laser light 40, it is possible to select a laser light with an appropriate wavelength according to the materials forming the semiconductor substrate 201 and the LED chip 202Ra. For example, when using a semiconductor material that absorbs laser light with a wavelength longer than that of ultraviolet light, a blue laser (blue light) or a green laser (green light) can be used.

In the process shown in FIG. 4, as the laser beam 40, a rectangular laser beam having an irradiation area large enough to include a plurality of openings 30a is used. When the irradiation area of the laser light 40 is narrower than the light-shielding mask 30, irradiation may be performed multiple times while moving the irradiation area of the laser light. In addition, the light-shielding mask 30 may be scanned by using a laser beam having a linear (elongated shape) irradiation area as the laser beam 40 without being limited to this example.

The laser light 40 applied to the light shielding mask 30 passes through only the portions where the openings 30a are located. That is, by using the light-shielding mask 30, it is possible to perform selective laser irradiation while using laser light with a wide irradiation area. In this embodiment, the position where the LED chip 202R is arranged is selectively irradiated with the laser beam 40 . As a result, the surface layer portion of the LED chip 202Ra (the boundary portion with the semiconductor substrate 201) is modified, and the semiconductor substrate 201 and each LED chip 202Ra can be separated.

The size (area) of the opening 30a may be any size that ensures separation between the LED chip 202Ra and the semiconductor substrate 201 in plan view. For example, the size of the opening 30a in plan view may be smaller than the size of the LED chip 202Ra. Also, the size of the opening 30a may be substantially the same as the size of the LED chip 202Ra, or may be slightly larger than the size of the LED chip 202Ra.

Next, in step S14 of FIG. 1, by selectively irradiating the LED chips 202Rb of the second group among the plurality of LED chips 202R with the laser beam 40, the LED chips 202Rb of the second group are removed from the element substrate 200. Separate (see Figure 6). Specifically, as shown in FIG. 6, the semiconductor substrate 201 and the LED chips 202Rb are collectively separated by irradiating the laser light 40 through the light shielding mask 30 . This process is laser lift-off, similar to the process shown in FIG.

In the process shown in FIG. 6, only the LED chips 202Rb of the second group among the plurality of LED chips 202R included in the element substrate 200 are irradiated with the laser light 40. In the process shown in FIG. As described above, the LED chips 202Rb of the second group are arranged in a staggered arrangement like the LED chips 202Ra of the first group. Therefore, in the process shown in FIG. 6, the same light shielding mask 30 as in the process shown in FIG. 4 can be used. Therefore, in this embodiment, after the process shown in FIG. 4 is performed, the process shown in FIG. 6 can be continuously performed only by shifting the position of the light shielding mask 30 . Details of the process shown in FIG. 6 are the same as the process shown in FIG.

After performing the lift-off process shown in FIGS. 4 and 6, the semiconductor substrate 201 and each LED chip 202R are separated. Specifically, the semiconductor substrate 201 is physically separated from the carrier substrate 301 . At this time, each LED chip 202</b>R remains on the carrier substrate 301 because it is adhered to the carrier substrate 301 . Thereby, a plurality of LED chips 202R can be transferred onto the carrier substrate 301 as shown in FIG.

As described above, in this embodiment, the separation of the LED chips R by laser lift-off is performed in two steps. In this case, the density of the LED chips 202R to be processed in one lift-off process is reduced as shown in FIG. The reason will be explained below. Further, as will be described later, the separation of the LED chips R may be performed in two or more steps.

As described above, the laser light 40 (in this case, ultraviolet light) emitted from the semiconductor substrate 201 side passes through the semiconductor substrate 201 made of sapphire and is absorbed by the semiconductor layer (eg, GaN layer). In this embodiment, since the laser light 40 with a short wavelength and high energy density is used, the semiconductor layer that rapidly absorbs energy instantaneously sublimates to generate gas. At this time, if the density of the LED chips 202R to be processed is high, the amount of gas generated is also large. Therefore, a phenomenon may occur in which the position of the LED chip 202R adhered to the carrier substrate 301 is displaced due to the impact caused by the generation of a large amount of gas.

FIG. 8A is a plan view showing the state of the LED chip 202 adhered to the carrier substrate 301 in the manufacturing method of the display device 10 according to the first embodiment. FIG. 8B is a plan view showing the state of the LED chip adhered to the carrier substrate in the manufacturing method of the display device in the comparative example. Specifically, FIG. 8B shows an example in which the lift-off process is collectively performed on the LED chips 202 included in the element substrate 200 .

As shown in FIG. 8A, according to the present embodiment, the plurality of LED chips 202 are not disorderly arranged on the carrier substrate 301, and the respective LED chips 202 are arranged orderly in the row direction and the column direction. This is because, according to the present embodiment, the number of LED chips to be processed in each lift-off process is half of the total, so the amount of generated gas is reduced. Furthermore, as shown in FIG. 5, the LED chips 202 to be processed are arranged in a staggered arrangement, so there are no adjacent LED chips 202 in the row and column directions. Therefore, individual LED chips 202 are less likely to be affected by gases generated by adjacent LED chips.

On the other hand, as shown in FIG. 8B, according to the comparative example, the arrangement of the plurality of LED chips 202 on the carrier substrate 301 is greatly disturbed. This is because, in the case of the comparative example, the amount of gas generated is twice that of the present embodiment, and the distance between adjacent LED chips 202 is short, so they are susceptible to mutual influence.

As described above, in this embodiment, when transferring a plurality of LED chips 202 from the element substrate 200 to the carrier substrate 301, the separation process by laser lift-off is performed in multiple steps. As a result, the amount of gas generated in each process can be reduced, and the influence of the gas generated by adjacent LED chips can be reduced. As a result, it is possible to prevent misalignment of the LED chips 202 adhered to the carrier substrate 301 and improve the yield when separating the LED chips 202 from the semiconductor substrate using laser irradiation.

Next, a process after transferring the plurality of LED chips 202R to the carrier substrate 301 will be described.

As shown in FIG. 9, the carrier substrate 301 is adhered to the carrier substrate 401 via the plurality of LED chips 202R. Like the carrier substrate 301, the carrier substrate 401 is a sheet member made of silicon or acrylic and has adhesiveness. The adhesive force of the carrier substrate 401 can be adjusted by laser light irradiation or the like. A known carrier substrate can be used as such a carrier substrate 401 .

Next, as shown in FIG. 10, carrier substrate 301 is separated from carrier substrate 401 . There is no particular limitation on the method of peeling off the carrier substrate 301 . For example, by setting the adhesive force for fixing each LED chip 202 to the carrier substrate 401 larger than the adhesive force for fixing each LED chip 202 to the carrier substrate 301, the carrier substrate 301 can be physically separated. . Further, ultraviolet light is irradiated from the carrier substrate 301 side to denature the interface between the carrier substrate 301 and each LED chip 202 (specifically, the terminal electrode of each LED chip 202), and then the carrier substrate is physically 301 may be peeled off.

Next, as shown in FIG. 11, the carrier board 401 is arranged on the circuit board 100 so that the connection electrodes 103 face each LED chip 202R. Specifically, the circuit board 100 and the carrier board 401 are aligned so that the terminal electrode 203R and the connection electrode 103 of each LED chip 202R are in contact with each other. An adhesive substance may be provided between the terminal electrode 203R and the connection electrode 103. FIG.

The circuit board 100 has regions corresponding to a plurality of pixels. As shown in FIG. 11, the circuit board 100 has a drive circuit 102 for driving an LED chip corresponding to each pixel on a substrate 101 having an insulating surface. As the substrate 101, for example, a glass substrate, a resin substrate, a ceramic substrate, or a metal substrate can be used. Each drive circuit 102 is composed of a plurality of thin film transistors (TFTs). Each connection electrode 103 is arranged in each pixel and connected to the drive circuit 102 . A detailed structure of the circuit board 100 will be described later.

In this embodiment, an example in which each drive circuit 102 and each connection electrode 103 are formed on a substrate 101 using a thin film formation technique is shown, but the present invention is not limited to this example. For example, a substrate in which the driver circuit 102 is formed on the substrate 101 (a so-called active matrix substrate) may be acquired from a third party as an off-the-shelf product. In this case, the connection electrodes 103 may be formed on the obtained substrate.

Also, in the present embodiment, a flip-chip type LED chip is described as an example of the LED chip 202, but the LED chip 202 is not limited to this example. For example, the LED chip 202 may have an anode electrode (or cathode electrode) on the side closer to the circuit board 100 and a cathode electrode (or anode electrode) on the side farther from the circuit board 100 . That is, the LED chip 202 may be a face-up type LED chip having a structure in which a light-emitting layer of an anode electrode and a cathode electrode is sandwiched. In this case, one connection electrode 103 may be provided for each pixel.

The connection electrode 103 is made of, for example, a conductive metal material. In this embodiment, tin (Sn) is used as the metal material. However, it is not limited to this example, and other metal materials that can form a eutectic alloy with terminal electrodes on the LED chip side, which will be described later, can be used. The thickness of the connection electrode 103 may be determined within the range of 0.2 μm to 5 μm (preferably 1 μm to 3 μm).

Next, as shown in FIG. 12, the connection electrodes 103 and the LED chips 202R are collectively bonded by irradiating the laser light 50 through the light shielding mask 35. Next, as shown in FIG. This process is a process of melting and joining the connection electrode 103 and the terminal electrode 203R of the LED chip 202R by irradiating the laser beam 50 .

As the laser beam 50, a laser beam that is absorbed by the connection electrode 103 or the terminal electrode 203R without being absorbed by the carrier substrate 401 and the LED chip 202R is selected. In this embodiment, for example, infrared light or near-infrared light can be used as the laser light 50 . A solid-state laser such as a YAG laser or a YVO ₄ laser may be used as the light source of the laser light 50 . However, for the laser light 50, it is possible to select a laser light with an appropriate wavelength according to the material forming the LED chip 202R. For example, when using a semiconductor material that absorbs laser light with a shorter wavelength than infrared light, it is also possible to use a green laser (green light).

An alloy layer (not shown) composed of a eutectic alloy is formed between the connection electrode 103 and the terminal electrode 203R by irradiation with the laser beam 50 . As described above, in this embodiment, the connection electrode 103 is made of tin (Sn). On the other hand, the terminal electrode 203R is made of gold (Au). That is, in the present embodiment, a layer made of Sn—Au eutectic alloy is formed as the alloy layer. By forming an alloy layer made of a eutectic alloy between the connection electrode 103 and the terminal electrode 203R, the connection electrode 103 and the terminal electrode 203R are firmly bonded via the alloy layer.

In this embodiment, a light-shielding mask 35 having a plurality of openings 35a is used when the laser beam 50 is applied. The plurality of openings 35a are arranged, for example, in accordance with each pitch (interval between pixels) of pixels corresponding to red, pixels corresponding to green, or pixels corresponding to blue. In the example shown in FIG. 12, the openings 35a are arranged according to the pitch of the pixels corresponding to red. That is, the position of each opening 35a corresponds to the position where the LED chip 202R is arranged.

In this embodiment, as the laser beam 50, a rectangular laser beam having an irradiation area with a size including a plurality of openings 35a is used. When the irradiation area of the laser light 50 is narrower than the light shielding mask 35, the entire light shielding mask 35 can be irradiated with the laser light 50 by irradiating multiple times while moving the irradiation area of the laser light. .

The laser light 50 applied to the light shielding mask 35 passes through only the portions where the openings 35a are located. That is, by using the light shielding mask 35, it is possible to perform selective laser irradiation while using laser light with a wide irradiation area. In this embodiment, the position where the LED chip 202R is arranged is selectively irradiated with the laser light 50 . In other words, according to this embodiment, the connection electrodes 103 and the LED chips 202R can be jointed together.

The size (area) of the opening 35a may be any size that ensures reliable bonding between the connection electrode 103 and the terminal electrode 203R in plan view. For example, the size of the opening 35a in plan view may be smaller than the size of the LED chip 202R. Also, the size of the opening 35a may be substantially the same as the size of the LED chip 202R, or may be slightly larger than the size of the LED chip 202R.

In this embodiment, an example of using a laser beam with a rectangular irradiation area as the laser beam 50 is shown, but the irradiation area is not limited to this example, and a laser beam with a linear (elongated shape) irradiation area may be used. . In this case, by scanning the light-shielding mask 35 with linear laser light, the entire light-shielding mask 35 can be irradiated with the laser light.

After irradiation with the laser beam 50, the carrier substrate 401 is peeled off as shown in FIG. Carrier substrate 401 may be physically peeled off. In this case, the LED chips 202R that are not irradiated with the laser light 50 remain on the carrier substrate 401 because they are not bonded to the circuit board 100 . On the other hand, the LED chip 202R irradiated with the laser light 50 in the process shown in FIG. 12 remains on the circuit board 100 because it is firmly bonded to the circuit board 100.

Through the process described above, the LED chip 202R corresponding to red is mounted on the circuit board 100. FIG. Since the LED chip 202G corresponding to green and the LED chip 202B corresponding to blue can be mounted on the circuit board 100 by the same manufacturing method as the LED chip 202R corresponding to red, detailed description thereof is omitted. do. As shown in FIG. 14, the LED chip 202R corresponding to red, the LED chip 202G corresponding to green, and the LED chip 202B corresponding to blue are each connected to the driving circuit 102 on the circuit board 100. FIG.

[Configuration of display device]
The configuration of the display device 10 according to the first embodiment of the present invention will be described with reference to FIGS. 15 to 18. FIG.

FIG. 15 is a plan view showing a schematic configuration of the display device 10 according to the first embodiment. As shown in FIG. 15, the display device 10 has a circuit board 100, a flexible printed circuit board 160 (FPC 160), and an IC chip 170. FIG. The display device 10 is divided into a display area 112 , a peripheral area 114 and a terminal area 116 .

The display area 112 is an area in which a plurality of pixels 110 including the LED chips 202 are arranged in the row direction (D1 direction) and the column direction (D2 direction). Specifically, in this embodiment, a pixel 110R including an LED chip 202R, a pixel 110G including an LED chip 202G, and a pixel 110B including an LED chip 202B are arranged. The display area 112 functions as an area for displaying an image according to the video signal.

Peripheral area 114 is the area around display area 112 . Driver circuits (data driver circuit 130 and gate driver circuit 140 shown in FIG. 16) for controlling pixel circuits (pixel circuit 120 shown in FIG. 17) provided in each pixel 110 are provided in the peripheral region 114. area.

A terminal area 116 is an area where a plurality of wirings connected to the driver circuit described above are concentrated. Flexible printed circuit board 160 is electrically connected to a plurality of wires in terminal area 116 . A video signal (data signal) or control signal output from an external device (not shown) is input to the IC chip 170 via wiring (not shown) provided on the flexible printed circuit board 160 . The IC chip 170 performs various signal processing on video signals and generates control signals necessary for display control. Video signals and control signals output from the IC chip 170 are input to the display device 10 via the flexible printed circuit board 160 .

[Circuit Configuration of Display Device 10]
FIG. 16 is a block diagram showing the circuit configuration of the display device 10 according to the first embodiment. As shown in FIG. 16, the display area 112 is provided with pixel circuits 120 corresponding to the respective pixels 110 . In this embodiment, pixel circuits 120R, 120G and 120B are provided corresponding to the pixels 110R, 110G and 110B, respectively. That is, in the display area 112, a plurality of pixel circuits 120 are arranged in the row direction (D1 direction) and the column direction (D2 direction).

FIG. 17 is a circuit diagram showing the configuration of the pixel circuit 120 of the display device 10 according to the first embodiment. The pixel circuits 120 are arranged in a region surrounded by data lines 121 , gate lines 122 , anode power lines 123 and cathode power lines 124 . The pixel circuit 120 of this embodiment includes a selection transistor 126 , a drive transistor 127 , a storage capacitor 128 and an LED 129 . LED 129 corresponds to each LED chip 202 shown in FIG. Circuit elements other than the LED 129 in the pixel circuit 120 correspond to the drive circuit 102 provided on the circuit board 100 . That is, the pixel circuit 120 is completed with the LED chip 202 mounted on the circuit board 100 .

As shown in FIG. 17, the source electrode, gate electrode and drain electrode of the select transistor 126 are connected to the data line 121, the gate line 122 and the gate electrode of the drive transistor 127, respectively. The source electrode, gate electrode and drain electrode of the driving transistor 127 are connected to the anode power line 123, the drain electrode of the selection transistor 126 and the LED 129 respectively. A storage capacitor 128 is connected between the gate electrode and the drain electrode of the drive transistor 127 . That is, the holding capacitor 128 is connected to the drain electrode of the select transistor 126 . The anode and cathode of the LED 129 are connected to the drain electrode of the drive transistor 127 and the cathode power supply line 124, respectively.

A gradation signal that determines the light emission intensity of the LED 129 is supplied to the data line 121 . The gate line 122 is supplied with a gate signal for selecting a selection transistor 126 for writing a gradation signal. When the selection transistor 126 is turned on, the gradation signal is accumulated in the holding capacitor 128 . After that, when the drive transistor 127 is turned on, a drive current corresponding to the gradation signal flows through the drive transistor 127 . When the driving current output from the driving transistor 127 is input to the LED 129, the LED 129 emits light with an emission intensity corresponding to the gradation signal.

Referring to FIG. 16 again, a data driver circuit 130 is arranged adjacent to the display area 112 in the column direction (D2 direction). A gate driver circuit 140 is arranged at a position adjacent to the display area 112 in the row direction (D1 direction). In this embodiment, two gate driver circuits 140 are provided on both sides of the display area 112, but only one of them may be provided.

Both the data driver circuit 130 and the gate driver circuit 140 are arranged in the peripheral region 114 . However, the area where the data driver circuit 130 is arranged is not limited to the peripheral area 114 . For example, data driver circuitry 130 may be located on flexible printed circuit board 160 .

The data line 121 shown in FIG. 17 extends in the D2 direction from the data driver circuit 130 and is connected to the source electrode of the select transistor 126 in each pixel circuit 120. The data line 121 shown in FIG. The gate line 122 extends in the D1 direction from the gate driver circuit 140 and is connected to the gate electrode of the select transistor 126 in each pixel circuit 120 .

A terminal portion 150 is arranged in the terminal region 116 . The terminal section 150 is connected to the data driver circuit 130 via a connection wiring 151 . Similarly, the terminal section 150 is connected to the gate driver circuit 140 via the connection wiring 152 . Furthermore, the terminal part 150 is connected to the flexible printed circuit board 160 .

[Cross-sectional structure of display device 10]
FIG. 18 is a cross-sectional view showing the configuration of the pixel 110 of the display device 10 according to the first embodiment. The pixel 110 has a drive transistor 127 provided on the insulating substrate 11 . As the insulating substrate 11, a substrate having an insulating layer provided on a glass substrate or a resin substrate can be used.

The driving transistor 127 includes a semiconductor layer 12 , a gate insulating layer 13 and a gate electrode 14 . A source electrode 16 and a drain electrode 17 are connected to the semiconductor layer 12 via an insulating layer 15 . Although not shown, the gate electrode 14 is connected to the drain electrode of the selection transistor 126 shown in FIG.

A wiring 18 is provided in the same layer as the source electrode 16 and the drain electrode 17 . The wiring 18 functions as the anode power supply line 123 shown in FIG. Therefore, the source electrode 16 and the wiring 18 are electrically connected by the connection wiring 20 provided on the planarization layer 19 . The planarizing layer 19 is a transparent resin layer using a resin material such as polyimide or acryl. The connection wiring 20 is a transparent conductive layer using a metal oxide material such as ITO. However, the connection wiring 20 is not limited to this example, and other metal materials can also be used.

An insulating layer 21 made of silicon nitride or the like is provided on the connection wiring 20 . An anode electrode 22 and a cathode electrode 23 are provided on the insulating layer 21 . In this embodiment, the anode electrode 22 and the cathode electrode 23 are transparent conductive layers using a metal oxide material such as ITO. The anode electrode 22 is connected to the drain electrode 17 through openings provided in the planarizing layer 19 and the insulating layer 21 .

The anode electrode 22 and the cathode electrode 23 are connected to mounting pads 25a and 25b through the planarization layer 24, respectively. The mounting pads 25a and 25b are made of a metal material such as tantalum or tungsten. Connection electrodes 103a and 103b are provided on the mounting pads 25a and 25b, respectively. The connection electrodes 103a and 103b respectively correspond to the connection electrode 103 shown in FIG. That is, in this embodiment, electrodes made of tin (Sn) are arranged as the connection electrodes 103a and 103b.

Terminal electrodes 203a and 203b of the LED chip 202 are joined to the connection electrodes 103a and 103b, respectively. As described above, in this embodiment, the terminal electrodes 203a and 203b are electrodes made of gold (Au).

The LED chip 202 corresponds to the LED 129 in the circuit diagram shown in FIG. That is, the terminal electrode 203 a of the LED chip 202 is connected to the anode electrode 22 connected to the drain electrode 17 of the driving transistor 127 . A terminal electrode 203 b of the LED chip 202 is connected to the cathode electrode 23 . Cathode electrode 23 is electrically connected to cathode power supply line 124 shown in FIG.

The display device 10 of the present embodiment having the structure described above has the advantage that the LED chip 202 is strongly mounted by fusion bonding by laser irradiation, so that it is highly resistant to impact and the like.

<Second embodiment>
In this embodiment, a method for manufacturing the display device 10 by a method different from that of the first embodiment will be described. Specifically, in this embodiment, when separating the LED chips 202R from the element substrate 200, an example is shown in which the plurality of LED chips 202R are divided into four groups and processed. Although the LED chip 202R corresponding to red is taken as an example, the same applies to the LED chip 202G corresponding to green and the LED chip 202B corresponding to blue. It should be noted that since the second embodiment is the same as the first embodiment except that the plurality of LED chips 202R are divided into four groups, redundant description will be omitted.

FIG. 19 is a plan view for explaining the arrangement of the first group of LEDs 202Ra, the second group of LEDs 202Rb, the third group of LEDs 202Rc, and the fourth group of LEDs 202Rd. As shown in FIG. 19, the first group of LED chips 202Ra, the second group of LED chips 202Rb, the third group of LED chips 202Rc, and the fourth group of LED chips 202Rd are each arranged in rows and columns. are placed every other That is, in each of the LED chips 202R of the first group to the fourth group, when focusing on one LED chip 202R, the eight adjacent LED chips 202R all belong to another group.

In the case of this embodiment, the number of LED chips R to be processed in one lift-off process (irradiation process of the laser light 40 shown in FIG. 4) is 1/4 of the plurality of LED chips 202R included in the element substrate 200. is. Therefore, in this embodiment, the lift-off process is performed four times in total. However, the four processes can be performed continuously by shifting the position of the light-shielding mask 30, so the throughput is not greatly reduced.

According to the present embodiment, the amount of gas generated is 1/2 compared to the first embodiment (1/4 compared to the comparative example), and the distance between the adjacent LED chips 202R is increased. Since they are long, they have the advantage that they are less likely to be influenced by each other.

<Third Embodiment>
In this embodiment, a method for manufacturing the display device 10 by a method different from that of the first embodiment will be described. Specifically, in this embodiment, when separating the LED chips 202R from the element substrate 200, an example is shown in which the plurality of LED chips 202R are divided into two groups and processed in a manner different from that of the first embodiment. Although the LED chip 202R corresponding to red is taken as an example, the same applies to the LED chip 202G corresponding to green and the LED chip 202B corresponding to blue. It should be noted that since the second embodiment is the same as the first embodiment except that the plurality of LED chips 202R are divided into four groups, redundant description will be omitted.

20 and 21 are plan views for explaining the arrangement of the first group of LEDs 202Ra and the second group of LEDs 202Rb in the third embodiment. In the example shown in FIG. 20, the LED chips 202Ra of the first group and the LED chips 202Rb of the second group are arranged continuously in the row direction and alternately arranged in the column direction. That is, for each of the LED chips 202Ra in the first group and the LED chips 202Rb in the second group, when one LED chip 202R is focused, two LED chips 202R adjacent in the column direction belong to the other group. ing.

On the other hand, in the example shown in FIG. 21, the LED chips 202Ra of the first group and the LED chips 202Rb of the second group are arranged continuously in the column direction and alternately arranged in the row direction. That is, in each of the LED chips 202Ra of the first group and the LED chips 202Rb of the second group, when one LED chip 202R is focused, two LED chips 202R adjacent in the row direction belong to the other group. ing.

In the case of this embodiment, the number of LED chips R to be processed in one lift-off process is 1/2 of the plurality of LED chips 202R included in the element substrate 200, as in the first embodiment. Therefore, according to the present embodiment, the amount of gas generated is the same as in the first embodiment (halved compared to the comparative example).

<Fourth Embodiment>
A common point among the first, second, and third embodiments described above is that when focusing on an arbitrary group of LED chips 202, the LED chips 202 adjacent in the row direction and/or the column direction It is a point belonging to another group. That is, when each position of the LED chips in the first group among the plurality of LED chips arranged in M rows×N columns (M and N are integers of 1 or more) is represented by (M _x , N _y ) , each position of the second group of LED chips is denoted by (M _x±1 , N _y ) or (M _x , N _y±1 ). In particular, in the case of the second embodiment, when each position of the LED chips in the first group is represented by (M _x , N _y ), each position of the LED chips in the second group is represented by (M _x±1 , N _y ), each position of the LED chips of the third group is represented by (M _x , N _y±1 ), and each position of the LED chips of the fourth group is represented by (M _x±1 , N _{y± 1} ).

As described above, as long as the conditions of the present embodiment are satisfied, regardless of how the plurality of LED chips 202 are divided into the plurality of groups, the yield in separating the LED chips and the semiconductor substrate using laser irradiation can be increased. can be improved. For example, the LED chips 202 included in the element substrate 200 may be divided into groups of four or more for processing.

<Fifth Embodiment>
In this embodiment, a method for manufacturing the display device 10 by a method different from that of the first embodiment will be described. Specifically, in this embodiment, an example in which the LED chip 202R is directly mounted on the circuit board 100 from the carrier board 301 will be described. Although the LED chip 202R corresponding to red is taken as an example, the same applies to the LED chip 202G corresponding to green and the LED chip 202B corresponding to blue. In addition, in the description using the drawings, items common to the first embodiment are denoted by common reference numerals, and overlapping descriptions are omitted.

22 to 27 are cross-sectional views showing the manufacturing method of the display device 10 according to the fifth embodiment. A plurality of LED chips 202R are transferred to the carrier substrate 301 shown in FIG. The process of transferring the plurality of LED chips 202R onto the carrier substrate 301 may follow the process described with reference to FIGS. 1 to 7 in the first embodiment.

The transfer member 410 includes a support member 411 and elastic members 412 . The support member 411 is a member that supports the elastic member 412 . As a material for forming the support member 411, a material having higher rigidity than the elastic member 412, such as glass, quartz, sapphire, silicon, and stainless steel, can be used.

The elastic member 412 has a function of picking up or releasing an element such as an LED chip. At that time, the elastic member 412 has a function of absorbing the repulsive force from the element. Natural rubber, synthetic rubber, or the like can be used as the material forming the elastic member 412 .

As shown in FIG. 22, the elastic member 412 has projections 412a. The cross-sectional size of the protrusion 412a corresponds to the size of an element such as an LED chip. In other words, the transfer member 410 is configured such that each element can be individually picked up or released using the protrusions 412a. In this embodiment, the pitch of the projections 412a (distance between two adjacent projections 412a) is greater than the pitch of each LED chip 202R (distance between two adjacent LED chips 202). In other words, as shown in FIG. 22, the protrusions 412a can selectively pick up the LED chips 202R at predetermined intervals. In the example shown in FIG. 23, the pitch of the protrusions 412a is three times the pitch of each LED chip 202R.

As shown in FIG. 22 , the transfer member 410 is arranged such that the tip of the protrusion 412 a faces the LED chip 202 a on the carrier substrate 301 . When the transfer member 410 is brought closer to the carrier substrate 301 in this state, the protrusion 412a comes into contact with the LED chip 202R.

FIG. 23 shows a state in which the protrusion 412a is in contact with the LED chip 202R. As shown in FIG. 23, every two protrusions 412a abut on the LED chips 202R. At this time, by pressing the transfer member 410 against the carrier substrate 301 with a predetermined pressure, the protrusions 412a are brought into close contact with the LED chips 202R. Since the protrusion 412a has elasticity, it absorbs the repulsive force from the LED chip 202R by shrinking.

Next, as shown in FIG. 24, when the transfer member 410 is moved away from the carrier substrate 301, the LED chip 202R in contact with the protrusion 412a is picked up. At this time, the adhesive force between the protrusion 412 a and the LED chip 202 R is set to be greater than the adhesive force between the LED chip 202 R and the carrier substrate 301 . The adhesive force between the protrusions 412a and the carrier substrate 301 can be adjusted by the type of adhesive used, the type of surface treatment of the protrusions 412a and the carrier substrate 301, and the like.

After selectively picking up the LED chips 202R using the transfer member 410 as described above, the transfer member 410 is placed on the circuit board 100 as shown in FIG. The transfer member 410 is arranged such that the tip of the protrusion 412 a (strictly speaking, the terminal electrode 203 R of the LED chip 202 R) faces the connection electrode 103 on the circuit board 100 .

When the transfer member 410 is brought closer to the circuit board 100 in this state, the terminal electrodes 203 and the connection electrodes 103 come into contact with each other as shown in FIG. Although not shown, a conductive adhesive (for example, an anisotropic conductive film) is provided on the connection electrodes 103 . Therefore, the terminal electrode 203 and the connection electrode 103 are adhered via a conductive adhesive. When the terminal electrode 203 and the connection electrode 103 are adhered to each other, the conductive adhesive can be solidified by applying heat or irradiating light. However, the present invention is not limited to this example, and instead of the connection electrode 103, a bump made of a conductive adhesive may be provided, and the bump and the terminal electrode 203R may be directly bonded. Further, the terminal electrode 203R and the connection electrode 103 may be temporarily bonded with an adhesive, and the terminal electrode 203R and the connection electrode 103 may be fused and bonded by irradiation with laser light.

After bonding each LED chip 202R to the connection electrode 103 on the circuit board 100 by the process shown in FIG. 26, the transfer member 410 is moved away from the circuit board 100 as shown in FIG. When the transfer member 410 is moved away from the circuit board 100, the LED chip 202R in contact with the protrusion 412a is released. The adhesive force between the protrusion 412a and the LED chip 202R is smaller than the adhesive force between the terminal electrode 203R of the LED chip 202R and the connection electrode 103. Therefore, the LED chip 202R can be easily released simply by moving the transfer member 410 away from the circuit board 100. FIG.

Through the process described above, the LED chip 202R corresponding to red is mounted on the circuit board 100. FIG. The LED chip 202G corresponding to green and the LED chip 202B corresponding to blue can be mounted on the circuit board 100 by the same manufacturing method as the LED chip 202R corresponding to red. Through these processes, as shown in FIG. 14, the LED chip 202R corresponding to red, the LED chip 202G corresponding to green, and the LED chip 202B corresponding to blue can be mounted on the circuit board 100. .

In this embodiment, an example of picking up and releasing the LED chip 202R using the adhesive force of the elastic member 412 (specifically, the protrusion 412a) of the transfer member 410 is shown, but the present invention is not limited to this example. do not have. For example, it is also possible to pick up and release the LED chip 202R using the suction force of vacuum suction or the like. Further, in the present embodiment, an example in which a plurality of LED chips 202R are collectively transferred has been shown, but the present invention is not limited to this example, and individual transfer is also possible.

Each of the embodiments described above as embodiments of the present invention can be implemented in combination as appropriate as long as they do not contradict each other. Based on each embodiment, a person skilled in the art appropriately adds, deletes, or changes the design of components, or adds, omits, or changes the conditions of steps, and also includes the gist of the present invention. as long as it is within the scope of the present invention.

In addition, even if there are other effects that are different from the effects brought about by the aspects of each embodiment described above, those that are obvious from the description of this specification or those that can be easily predicted by those skilled in the art, Naturally, it is understood that it is brought about by the present invention.

DESCRIPTION OF SYMBOLS 10... Display apparatus 11... Insulating substrate 12... Semiconductor layer 13... Gate insulating layer 14... Gate electrode 15... Insulating layer 16... Source electrode 17... Drain electrode 18... Wiring 19... Flattening layer , 20... Connection wiring 21... Insulating layer 22... Anode electrode 23... Cathode electrode 24... Flattening layer 25a, 25b... Mounting pad 30, 35... Light shielding mask 30a, 35a... Opening 40, 50... Laser light 100... Circuit board 101... Substrate 102... Drive circuit 103, 103a, 103b... Connection electrodes 110, 110R, 110G, 110B... Pixels 112... Display area 114... Peripheral area 116... Terminal area 120, 120R, 120G, 120B... Pixel circuit 121... Data line 122... Gate line 123... Anode power supply line 124... Cathode power supply line 126... Selection transistor 127... Drive transistor 128... Holding capacity , 130... data driver circuit, 140... gate driver circuit, 150... terminal section, 151, 152... connection wiring, 160... flexible printed circuit board, 170... IC chip, 200... element substrate, 201... semiconductor substrate, 202, 202R , 202G, 202B...LED chips, 202Ra...first group of LED chips, 202Rb...second group of LED chips, 202Rc...third group of LED chips, 202Rd...fourth group of LED chips, 203a, 203b, 203R... Terminal electrodes 301, 401 Carrier substrate 410 Transfer member 411 Support member 412 Elastic member 412a Projection

Claims (10)

Prepare a first substrate having a plurality of LED chips arranged in M rows x N columns (M and N are integers of 1 or more),
bonding the first substrate to the second substrate through the plurality of LED chips;
By selectively irradiating the LED chips of the first group among the plurality of LED chips with laser light, the LED chips of the first group are separated from the first substrate,
separating the LED chips of the second group from the first substrate by selectively irradiating the LED chips of the second group among the plurality of LED chips with laser light;
When each position of the LED chips of the first group is represented by (M _x , N _y ), each position of the LED chips of the second group is (M _x±1 , N _y ) or (M _x , N _y±1 ),
A method for manufacturing a display device. By selectively irradiating the LED chips of the third group among the plurality of LED chips with laser light, the LED chips of the third group are separated from the first substrate,
2. The method according to claim 1, further comprising separating the fourth group of LED chips from the first substrate by selectively irradiating a fourth group of LED chips among the plurality of LED chips with laser light. A method of manufacturing the described display device. When each position of the LED chips in the first group is represented by (M _x , N _y ), each position of the LED chips in the second group is represented by (M _x±1 , N _y ), Each position of the LED chips of the third group is represented by (M _x , N _y±1 ), and each position of the LED chips of the fourth group is represented by (M _x±1 , N _y±1 ). 3. The method of manufacturing the display device according to claim 2, wherein 2. The method of manufacturing a display device according to claim 1, wherein said first group of LED chips and said second group of LED chips are arranged in a staggered arrangement. 5. The method of manufacturing a display device according to claim 1, wherein the number of LED chips in said first group and the number of LED chips in said second group are substantially the same. 6. The method according to any one of claims 1 to 5, wherein the selectively irradiating the laser light includes irradiating the first substrate with the laser light through a light-shielding mask having a plurality of openings. A method for manufacturing a display device. 7. The method of manufacturing a display device according to claim 6, wherein the pitch of said plurality of openings is at least twice the pitch of said plurality of LED chips. 8. The method of manufacturing a display device according to claim 6, wherein said selectively irradiating a laser beam includes scanning said light shielding mask with said laser beam. 9. The method of manufacturing a display device according to claim 1, wherein said laser light is ultraviolet light. The first substrate is an element substrate,
10. The method of manufacturing a display device according to claim 1, wherein said second substrate is a carrier substrate.

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