TWI825749B - Manufacturing method of display device - Google Patents

Abstract

An object of the present invention is to prevent diffraction of laser light in a display device installation method including an irradiation process of laser light using a light shield. The manufacturing method of the display device includes the following steps: preparing a first substrate provided with a plurality of LED chips, and arranging the plurality of LED chips on the above-mentioned substrate so that the plurality of LED chips are located between the first substrate and the second substrate. On the second substrate, a part of the plurality of LED chips is irradiated with laser light through a light shield fixed to the holding member holding the first substrate.

Description

Manufacturing method of display device

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

In recent years, as the next generation of display devices, there has been progress in the development of LED displays in which tiny LED chips are installed in each pixel. An LED display has a structure in which a plurality of LED chips are mounted on a circuit substrate that forms a pixel array. The circuit board has a drive circuit for causing the LED to emit light at a position corresponding to each pixel. The driving circuits are electrically connected to each LED chip respectively.

There are various methods for mounting multiple LED chips on a circuit substrate. For example, a method is known in which an LED chip and a circuit substrate provided on a supporting substrate are connected together, and then only the supporting substrate is removed. For example, Patent Document 1 describes a technology that uses a light shield to selectively irradiate laser light to an LED chip with a high throughput. [Prior technical literature] [Patent Document]

[Patent Document 1] U.S. Patent No. 10096740 Specification

[Problem to be solved by the invention]

As in the above-mentioned prior art, when there is a gap between the hood and the object irradiated with laser light, there is a risk that the laser light will be diffracted at the opening of the hood and the back side of the hood will be irradiated with laser light. . The longer the wavelength of laser light, the more significant the diffraction of laser light is.

One of the subjects of the present invention is to prevent the diffraction of laser light in a manufacturing method of a display device including an irradiation process of laser light using a light shield. [Technical means to solve problems]

A method for manufacturing a display device according to an embodiment of the present invention includes the following steps: preparing a first substrate provided with a plurality of LED chips, and placing the above-mentioned LED chips so that the plurality of LED chips are located between the first substrate and the second substrate. A plurality of LED chips are arranged on the second substrate, and a part of the plurality of LED chips is irradiated with laser light through a light shield fixed to a holding member that holds the first substrate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. However, the present invention can be implemented in various forms without departing from the scope of the invention. The present invention is not limited to the description of the embodiments illustrated below and shall not be construed. In order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual form. However, the drawings are only examples and do not limit the interpretation of the present invention.

When describing the embodiment of the present invention, the direction from the substrate toward the LED chip is referred to as “upper” and the opposite direction is referred to as “lower”. Among them, the expression "upper" or "lower" only indicates the upper-lower relationship between each element. For example, arranging an LED chip on a substrate also includes interposing other components between the substrate and the LED chip. Furthermore, the expression "up" or "down" is not only the case where the elements overlap when viewed from above, but also includes the case where there is no overlap.

When describing embodiments of the present invention, components having the same functions as those already described may be labeled with the same symbols or symbols such as English letters may be labeled with the same symbols, and descriptions thereof may be omitted. In addition, when it is necessary to explain a certain requirement by distinguishing between RGB colors, the symbol R, G, or B is added after the symbol showing the requirement to distinguish it. However, when the requirements do not need to be explained separately as RGB colors, only the symbols showing the requirements will be used for description.

<First Embodiment> [Manufacturing method of display device] FIG. 1 is a flowchart showing a method of manufacturing the display device 10 according to the first embodiment. Specifically, FIG. 1 shows the process of transferring a plurality of LED chips 202 formed on the device substrate 200 to the circuit substrate 100 . 2 to 5 are cross-sectional views showing the manufacturing method of the display device 10 of the first embodiment. Here, the process until the LED chip 202 of each RGB color is transferred to the circuit substrate 100 is explained using FIG. 1 . At this time, specific examples of each process will be described using Figures 2 to 5.

First, in step S11 of FIG. 1 , an element substrate 200 having a plurality of LED chips 202R is prepared (see FIG. 2 ). The plurality of LED chips 202R are LED chips that emit red light. The LED chip 202R can be formed by growing a semiconductor layer on the semiconductor substrate 201 . As the semiconductor substrate 201, for example, a sapphire substrate can be used. In addition, as the semiconductor layer, for example, gallium nitride (GaN) can be grown. However, the LED chip 202R is not limited to this example. For example, a semiconductor layer (for example, an InGaAlP layer) grown on another semiconductor substrate such as a gallium arsenide (GaAs) substrate may also be used to form the LED chip 202R. In this case, another semiconductor substrate on which the LED chip 202R is formed can also be used in conjunction with the semiconductor substrate 201 .

Next, in step S12 of FIG. 1 , the plurality of LED chips 202R are arranged on the circuit substrate 100 in such a manner that the plurality of LED chips 202R are located between the component substrate 200 and the circuit substrate 100 (see FIG. 3 ). Specifically, the element substrate 200 is arranged on the circuit substrate 100 so that the connection electrode 103 faces each LED chip 202R. At this time, the circuit substrate 100 and the element substrate 200 are aligned in such a manner that the terminal electrode 203R of each LED chip 202R is connected to the connection electrode 103 . An adhesive material may be provided between the terminal electrode 203R and the connection electrode 103 .

The circuit board 100 has an area corresponding to a plurality of pixels. As shown in FIG. 3 , the circuit substrate 100 has a driving circuit 102 corresponding to each pixel and driving the LED chip on the substrate 101 with 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). The circuit substrate 100 is also called an array substrate, a TFT substrate, or the like. Each connection electrode 103 is arranged in each pixel and connected to the driving circuit 102 respectively. The detailed structure of the circuit board 100 will be described later.

In this embodiment, an example is shown in which each drive circuit 102 and each connection electrode 103 are formed on the substrate 101 using thin film formation technology, but the invention is not limited to this example. For example, a substrate (so-called active matrix substrate) with the driving circuit 102 formed on the substrate 101 can also be obtained from a third party as a ready-made product. In this case, it is sufficient to form the connection electrode 103 on the obtained substrate.

Furthermore, in this embodiment, a flip-chip LED chip is exemplified as the LED chip 202R for description, but the invention is not limited to this example. For example, the LED chip 202R may have a structure in which an anode electrode (or a cathode electrode) is provided on a side close to the circuit substrate 100 and a cathode electrode (or anode electrode) is provided on a side far away from the circuit substrate 100 . That is, the LED chip 202R may be a face-up LED chip having a structure in which a light-emitting layer sandwiched an anode electrode and a cathode electrode. In this case, only one connection electrode 103 is 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, the present invention is not limited to this example, and other metal materials that can form a eutectic alloy with the terminal electrodes on the LED chip side described below may 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, in step S13 of FIG. 1 , a part of the plurality of LED chips 202R is irradiated with laser light 50 through the light shield 40 fixed to the holding member 30 of the holding element substrate 200 (see FIG. 4 ). As shown in FIG. 4 , in this embodiment, the connection electrode 103 and a part of the LED chip 202R are bonded together by irradiating the laser light 50 through the light shield 40 . This process is a process in which the connection electrode 103 and the terminal electrode 203R of the LED chip 202R are fused and bonded by irradiation of the laser light 50 .

As the laser light 50, a laser light that is not absorbed by the semiconductor substrate 201 and the LED chip 202R but is absorbed by the connection electrode 103 or the terminal electrode 203R is selected. In this embodiment, for example, near-infrared light can be used as the laser light 50 . As the light source of the laser light 50, solid lasers such as YAG laser or YVO ₄ laser can also be used. That is, the laser light 50 may also be the fundamental wave of the above-mentioned solid laser. However, the laser light 50 can select an appropriate wavelength of laser light according to the material constituting the LED chip 202R. For example, when using a semiconductor material that absorbs laser light with a shorter wavelength than near-infrared light, the second higher harmonic wave of the above-mentioned solid laser, that is, green laser (green light), can also be used.

By irradiating the laser light 50, an alloy layer (not shown) composed of a eutectic alloy is formed between the connection electrode 103 and the terminal electrode 203R. 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 this embodiment, a layer composed of Sn—Au eutectic alloy is formed as the alloy layer. By forming an alloy layer composed 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 joined through the alloy layer.

The light shield 40 has a plurality of openings 40a. The plurality of openings 40 a are arranged to match each pitch (inter-pixel pitch) of pixels corresponding to red, pixels corresponding to green, or pixels corresponding to blue, for example. In the example shown in FIG. 4 , each opening 40 a is arranged to match the pitch between pixels corresponding to red. That is, the position of each opening 40a corresponds to the position where the LED chip 202R is arranged.

As described above, the light shield 40 of this embodiment is fixed to the holding member 30 that holds the element substrate 200 . Specifically, as shown in FIG. 4 , the light shield 40 is connected to the holding member 30 . Therefore, the laser light 50 passes through the holding member 30 and the light shield 40 and is irradiated to the element substrate 200 . Therefore, in this embodiment, a material that transmits the fundamental wave or the second harmonic wave of the above-mentioned solid laser is used as the material of the holding member 30 . For example, the holding member 30 may be made of glass, quartz, or sapphire. The holding member 30 and the light shield 40 will be described later.

In this embodiment, a rectangular laser light having an irradiation area having a size including a plurality of openings 40 a is used as the laser light 50 . In addition, when the irradiation area of the laser light 50 is narrower than that of the light shield 40, the entire light shield 40 can be irradiated with the laser light 50 by moving the irradiation area of the laser light a plurality of times.

The laser light 50 irradiated to the light shield 40 only passes through the portion where the opening 40 a is located. That is, by using the light shield 40, selective laser irradiation can be performed 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 . That is, according to this embodiment, the plurality of connection electrodes 103 and the plurality of LED chips 202R can be bonded together.

The size (area) of the opening 40a may be a size that ensures the connection between the connection electrode 103 and the terminal electrode 203R when viewed from above. For example, the size of the opening 40a in plan view may be smaller than the size of the LED chip 202R. In addition, the size of the opening 40a may be the same as (including substantially the same) the size of the LED chip 202R, or may be slightly larger than the size of the LED chip 202R.

In addition, in this embodiment, although the example of using a laser light with a rectangular irradiation area as the laser light 50 is shown, the invention is not limited to this example, and a laser light with a linear (elongated shape) irradiation area may also be used. In this case, by scanning the light shielding cover 40 with linear laser light, the entire light shielding cover 40 can be irradiated with laser light.

After the laser light 40 is irradiated, as shown in FIG. 5 , the plurality of LED chips 202R irradiated by the laser light 50 are selectively irradiated with the laser light 60 . In this embodiment, an example is shown in which the above-described holding member 30 and light shielding cover 40 are directly used. However, the present embodiment is not limited to this example, and other light shielding covers may be used, or no light shielding cover may be used.

The process shown in FIG. 5 is a process of separating the semiconductor substrate 201 and the LED chip 202Ra by irradiating the laser light 60, which is called laser lift-off. As the laser light 60, a laser light that is not absorbed by the semiconductor substrate 201 and is absorbed by the LED chip 202Ra is selected. In this embodiment, ultraviolet light is used as the laser light 60 . As the light source of the laser light 60, a solid laser such as YAG laser or YVO ₄ laser, or an excimer laser can be used. For example, when using a solid-state laser, the second harmonic or the third harmonic can be used. However, the laser light 60 can select an appropriate wavelength of laser light according to the materials constituting the semiconductor substrate 201 and the LED chip 202Ra. For example, when using a semiconductor material that absorbs laser light with a longer wavelength than ultraviolet light, a blue laser (blue light) or a green laser (green light) can also be used.

In this embodiment, the LED chip 202R irradiated with the laser light 50 is selectively irradiated with the laser light 60 . 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 physically separated.

After the laser light 60 is irradiated, as shown in FIG. 6 , the element substrate 200 is peeled off. The element substrate 200 only needs to be physically peeled off. In this case, in the process shown in FIG. 5 , the LED chip 202R that has not been irradiated with the laser light 60 remains on the device substrate 200 . On the other hand, in the process shown in FIG. 5 , the LED chip 202R irradiated with the laser light 60 is firmly bonded to the circuit substrate 100 and thus remains on the circuit substrate 100 .

As described above, the LED chip 202R corresponding to red is mounted on the circuit substrate 100 . The LED chip 202G corresponding to green and the LED chip 202B corresponding to blue can be mounted on the circuit substrate 100 using the same manufacturing method as the LED chip 202R corresponding to red, so detailed description is omitted. Furthermore, in this embodiment, LED chips of various colors are arranged at the same pitch. Therefore, the above-mentioned holding member 30 and light shield 40 can be used when irradiating laser light 50 to LED chips of various colors by adjusting the position of the circuit substrate 100 .

After the process described so far, as shown in FIG. 7 , the LED chip 202R corresponding to red, the LED chip 202G corresponding to green, and the LED chip 202B corresponding to blue are respectively connected to the driving circuit 102 on the circuit substrate 100 .

[Construction of laser processing device] In this embodiment, the structure of the laser processing device 300 used in step S13 of FIG. 1 will be described.

FIG. 8 is a diagram showing the structure of the laser processing device 300 used in the manufacturing method of the display device 10 according to the first embodiment. As shown in FIG. 8 , the laser processing apparatus 300 includes a laser oscillator 302, a mirror 304, a beam expander 306, a first workpiece unit 308, and a second workpiece unit 310. However, the structure of the laser processing device 300 is not limited to this example. The reflector 304 or the beam expander 306 may be omitted, and other requirements may be added.

The laser oscillator 302 of this embodiment is an Nd:YAG laser using a solid material in which trivalent neodymium ions (Nd ³⁺ ) are added to YAG (Yttrium Aluminum Garnet: Y ₃ Al ₅ O ₁₂ ) crystal as a medium. The laser oscillator 302 outputs a fundamental wave (near-infrared light) with a wavelength of 1064 nm.

The optical path of the laser light 320a output from the laser oscillator 302 is changed by the reflecting mirror 304 and heads toward the beam expander 306. The beam expander 306 is composed of a lens system that expands the beam path of the input collimated light. By passing through the beam expander 306, the laser light 320a is output as the laser light 320b with an expanded beam diameter (ie, irradiation range). The laser light 320b corresponds to the laser light 50 shown in FIG. 4 .

In this embodiment, the case where the irradiation range of the laser light 320b is narrower than the area of the second workpiece unit 310 will be explained. In this case, by relatively moving the irradiation range of the laser light 320b with respect to the second workpiece unit 310, the area required for processing the object to be processed can be covered. In order to move the irradiation range of the laser light 320b, for example, the optical system composed of the laser oscillator 302, the reflecting mirror 304 and the beam expander 306 may also be moved. On the contrary, by moving the first workpiece unit 308 and the second workpiece unit 310, the irradiation range of the laser light 320b can be relatively moved.

The laser light 320b output from the beam expander 306 passes through the second workpiece unit 310 and is irradiated to the object to be processed (not shown) arranged between the first workpiece unit 308 and the second workpiece unit 310. In this embodiment, the LED chip 202 (for example, the LED chip 202R shown in FIG. 4 ) is the object to be processed.

The first workpiece unit 308 includes a holding member 70 and holds a substrate or the like that supports an object to be processed. In this embodiment, the holding member 70 has a function of holding the substrate and the like by vacuum suction. The material constituting the holding member 70 is not particularly limited, and for example, glass, quartz, ceramics, etc. may be used.

The second workpiece unit 310 includes a holding member 30 and a light shield 40, and holds a substrate and the like supporting an object to be processed. Like the holding member 70 , the holding member 30 has a function of holding the substrate and the like by vacuum suction. Furthermore, as described above, the light shield 40 is connected to the holding member 30 . In other words, the holding member 30 and the light shield 40 have an integrated structure.

In this embodiment, the holding member 30 is made of a material that transmits the laser light 320b. In this embodiment, since near-infrared light is used as the laser light 320b, it is desired to have the function of transmitting light with a wavelength of around 1.0 μm. Therefore, as a material constituting the holding member 30, for example, glass, quartz, sapphire, etc. can be used. However, it is not limited to this example, and the material constituting the holding member 30 can be appropriately selected according to the wavelength of the laser light used.

The light shield 40 has a plurality of openings 40a and can selectively transmit the laser light 320b through the plurality of openings 40a. The light shield 40 may be made of metal material such as Invar. When the holding member 30 is made of an insulating material such as glass, quartz or sapphire, the light shield 40 may be connected to the holding member 30 through an adhesive layer or the like.

FIG. 9 is a diagram showing how the laser processing device 300 is used to perform the irradiation process of the laser light 320b. The irradiation process shown in FIG. 9 is equivalent to the irradiation process of the laser light 50 shown in FIG. 4 .

As shown in FIG. 9 , the circuit board 100 is held by vacuum suction on the holding member 70 of the first workpiece unit 308 . On the holding member 30 of the second workpiece unit 310, the element substrate 200 is held by vacuum suction through the light shield 40. Therefore, the gap between the light shield 40 and the element substrate 200 disappears, and the element substrate 200 becomes in close contact with the light shield 40 .

With the circuit board 100 held on the holding member 70 and the element substrate 200 held on the holding member 30 (strictly speaking, the light shield 30 ), the circuit board 100 and the element substrate 200 are aligned. That is, as shown in FIG. 3 , the circuit substrate 100 and the element substrate 200 are arranged so that the connection electrode 103 of the circuit substrate 100 is connected to the terminal electrode 203R of the LED chip 202R.

After the alignment of the circuit substrate 100 and the element substrate 200 is completed, as shown in FIG. 9 , laser light 320b is irradiated. At this time, since the light shield 40 is in close contact with the element substrate 200, the laser light 320b passing through the plurality of openings 40a is incident on the element substrate 200 without being diffracted. Therefore, according to this embodiment, it is possible to selectively irradiate the laser light 320b to the LED chip 202R while preventing the diffraction of the laser light 320b.

Here, the structure of the second workpiece unit 310 holding the element substrate 200 will be described. Specifically, the structure of the holding member 30 and the light shield 40 which comprise the 2nd workpiece unit 310 is demonstrated.

FIG. 10 is a diagram showing the structure of the second workpiece unit 310 in the laser processing apparatus 300 used in the manufacturing method of the display device 10 of the first embodiment. Specifically, FIG. 10 corresponds to a view of the second workpiece unit 310 as viewed from the side holding the object to be processed. In addition, in FIG. 10 , the light shield 40 is arranged at the front of the second workpiece unit 310 . Therefore, for convenience of explanation, illustration of a part of the light shield 40 is omitted.

As shown in FIG. 10 , the holding surface 30 a of the holding member 30 has a processing area 31 and an adsorption area 32 . The processing area 31 is an area for irradiating the device substrate 200 , which is an object to be processed, with the laser light 320 b. The holding member 30 holds the element substrate 200 by vacuum-adsorbing the semiconductor substrate 201 of the element substrate 200 to the holding surface 30a. At this time, the plurality of LED chips 202 provided on the device substrate 200 are configured to be accommodated inside the processing area 31 . That is, when the element substrate 200 is held by the holding member 30 , the plurality of LED chips 202 are arranged in positions overlapping the processing area 31 .

The adsorption area 32 is an area used for vacuum adsorption of the component substrate 200 . As shown in FIG. 10 , the holding member 30 has a plurality of adsorption holes 32 a in the adsorption area 32 . That is, in the adsorption area 32 , a plurality of adsorption holes 32 a are used to adsorb the element substrate 200 . The adsorption area 32 is provided to surround the processing area 31 . In other words, when the element substrate 200 is held by the holding member 30 , the plurality of LED chips 202 do not overlap with the adsorption area 32 .

As mentioned above, the light shield 40 has a plurality of openings 40a. As shown in FIG. 10 , a plurality of openings 40 a are arranged inside the treatment area 31 . In addition, the light shield 40 has a plurality of adsorption holes 40b. The plurality of adsorption holes 40b are provided to overlap the adsorption area 32. That is, the plurality of adsorption holes 40b are provided so as to surround the plurality of openings 40a. At this time, the plurality of adsorption holes 32a provided in the holding member 30 and the plurality of adsorption holes 40b provided in the light shield 40 at least partially overlap. Preferably, the positions of each adsorption hole 32a and each adsorption hole 40b are consistent with each other (including substantially consistent). In this way, since the light shielding cover 40 is also provided with the adsorption holes 40b, the holding member 30 can adsorb the component substrate 200 through the light shielding cover 40.

In this embodiment, although the case where the adsorption hole 32a and the adsorption hole 40b has a circular outer shape is exemplified, it is not limited to this example. The outer shapes of the adsorption holes 32a and 40b may also be polygonal or elliptical. In addition, the adsorption holes 32a and the adsorption holes 40b do not need to be hole-shaped, and may be groove-shaped. For example, the adsorption holes 32 a and 40 b may also be concentric grooves along the holding member 30 .

As described above, the laser processing apparatus 300 of this embodiment includes the second workpiece unit 310 in which the holding member 30 and the light shield 40 are integrated, and has a structure in which the laser light 320b is irradiated to the object to be processed through the holding member 30. When the laser processing apparatus 300 of this embodiment is used, since there is no gap between the light shield 40 and the object to be processed (the device substrate 200 in this embodiment), it is possible to prevent the light shield 40 from passing through the opening. Diffraction of laser light in part 40a.

Furthermore, in this embodiment, since the laser light 320a output from the laser oscillator 302 is expanded and irradiated by the beam expander 306, a wide range of laser light irradiation can be performed at once. Therefore, according to this embodiment, the laser light irradiation process can be performed with a high throughput while preventing the diffraction of the laser light.

[Configuration of display device] The structure of the display device 10 according to the first embodiment of the present invention will be described using FIGS. 11 to 14 .

FIG. 11 is a plan view showing the schematic structure of the display device 10 according to the first embodiment. As shown in FIG. 11 , the display device 10 includes a circuit board 100 , a flexible printed circuit board 160 (FPC 160 ), and an IC chip 170 . 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 including a plurality of pixels 110 of the LED chip 202 arranged in the column direction (D1 direction) and the row direction (D2 direction). Specifically, in this embodiment, the pixel 110R including the LED chip 202R, the pixel 110G including the LED chip 202G, and the pixel 110B including the LED chip 202B are arranged. The display area 112 functions as an area for displaying an image corresponding to an image signal.

The peripheral area 114 is an area surrounding the display area 112 . The peripheral area 114 is an area provided with a driving circuit (the data driving circuit 130 and the gate driving circuit 140 shown in FIG. 16 ) for controlling the pixel circuit (the pixel circuit 120 shown in FIG. 17 ) provided in each pixel 110 .

The terminal area 116 is an area where a plurality of wirings connected to the drive circuit are collected. The flexible printed circuit board 160 is electrically connected to a plurality of wirings in the terminal area 116 . Image signals (data signals) or control signals output from an external device (not shown) are input to the IC chip 170 through wiring (not shown) provided on the flexible printed circuit board 160 . The IC chip 170 performs various signal processing on the image signal or generates control signals required for display control. The image signals and control signals output from the IC chip 170 are input to the display device 10 through the flexible printed circuit substrate 160 .

[Circuit configuration of display device 10] FIG. 12 is a block diagram showing the circuit configuration of the display device 10 of the first embodiment. As shown in FIG. 12 , a pixel circuit 120 is provided in the display area 112 corresponding to each pixel 110 . In this embodiment, pixel circuits 120R, pixel circuits 120G and pixel circuits 120B are respectively provided corresponding to the pixels 110R, 110G and 110B. That is, in the display area 112, a plurality of pixel circuits 120 are arranged in the column direction (D1 direction) and the row direction (D2 direction).

FIG. 13 is a circuit diagram showing the structure of the pixel circuit 120 of the display device 10 of the first embodiment. The pixel circuit 120 is arranged in an area surrounded by the data line 121, the gate line 122, the anode power line 123 and the cathode power line 124. The pixel circuit 120 of this embodiment includes a selection transistor 126, a driving transistor 127, a holding capacitor 128 and an LED 129. LED 129 corresponds to each LED chip 202 shown in FIG. 11 . In the pixel circuit 120, circuit elements other than the LED 129 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. 13 , the source electrode, gate electrode and drain electrode of the selection transistor 126 are respectively connected to the data line 121 , the gate line 122 and the gate electrode of the driving transistor 127 . The source electrode, gate electrode and drain electrode of the driving transistor 127 are respectively connected to the anode power line 123, the drain electrode of the selection transistor 126 and the LED 129. A holding capacitor 128 is connected between the gate electrode and the drain electrode of the driving transistor 127 . That is, the holding capacitor 128 is connected to the drain electrode of the selection transistor 126 . The LED 129 is connected to the anode and the cathode of the drain electrode and the cathode power line 124 of the driving transistor 127 respectively.

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

Referring to FIG. 12 again, the data driving circuit 130 is disposed adjacent to the display area 112 in the row direction (D2 direction). In addition, the gate driving circuit 140 is arranged at a position adjacent to the display area 112 in the column direction (D1 direction). In this embodiment, the gate driving circuit 140 is provided on the left and right sides of the display area 112, or it may be provided only on either side.

The data driving circuit 130 and the gate driving circuit 140 are both arranged in the peripheral area 114 . However, the area where the data driving circuit 130 is arranged is not limited to the peripheral area 114 . For example, the data driving circuit 130 can also be configured on the flexible printed circuit substrate 160 .

The data line 121 shown in FIG. 13 extends from the data driving circuit 130 in the D2 direction (refer to FIG. 12 ) and is connected to the source electrode of the selection transistor 126 in each pixel circuit 120 . The gate line 122 extends from the gate driving circuit 140 in the D1 direction (refer to FIG. 12 ) and is connected to the gate electrode of the selection transistor 126 in each pixel circuit 120 .

A terminal portion 150 is arranged on the end surface of the terminal area 116 . The terminal portion 150 is connected to the data driving circuit 130 via the connection wiring 151 . Similarly, the terminal portion 150 is connected to the gate drive circuit 140 via the connection wiring 152 . Furthermore, the terminal portion 150 is connected to the flexible printed circuit board 160 .

[Cross-sectional structure of display device 10] FIG. 14 is a cross-sectional view showing the structure of the pixel 110 of the display device 10 according to the first embodiment. The pixel 110 has a driving transistor 127 disposed on the insulating substrate 11 . As the insulating substrate 11, a substrate in which an insulating layer is 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 . The source electrode 16 and the drain electrode 17 are connected to the semiconductor layer 12 via the insulating layer 15 . Although illustration is omitted, the gate electrode 14 is connected to the drain electrode of the selection transistor 126 shown in FIG. 13 .

The wiring 18 is provided on 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. 13 . Therefore, the source electrode 16 and the wiring 18 are electrically connected through the connecting wiring 20 provided on the planarization layer 19 . The planarization layer 19 is a transparent resin layer using a resin material such as polyimide or acrylic. The connection wiring 20 is a transparent conductive layer using a metal oxide material such as ITO (Indium Tin Oxide). However, the present invention is not limited to this example, and other metal materials may be used as the connecting wire 20 .

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 made of metal oxide materials such as ITO. The anode electrode 22 is connected to the drain electrode 17 through openings provided in the planarization layer 19 and the insulating layer 21 .

The anode electrode 22 and the cathode electrode 23 are respectively connected to the mounting pads 25a and 25b via the planarization layer 24. The mounting pads 25a and 25b are made of metal materials such as tantalum and tungsten, for example. Connection electrodes 103a and 103b are respectively provided on the mounting pads 25a and 25b. The connection electrodes 103a and 103b respectively correspond to the connection electrode 103 shown in FIG. 3 . That is, in this embodiment, electrodes made of tin (Sn) are arranged as the connection electrodes 103a and 103b.

The terminal electrodes 203a and 203b of the LED chip 202 are bonded 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 is equivalent to the LED 129 in the circuit diagram shown in FIG. 13 . That is, the terminal electrode 230a of the LED chip 202 is connected to the anode electrode 22 to which the drain electrode 17 of the driving transistor 127 is connected. The terminal electrode 203b of the LED chip 202 is connected to the cathode electrode 23. The cathode electrode 23 is electrically connected to the cathode power supply line 124 shown in FIG. 13 .

The display device 10 of this embodiment having the above structure has the advantage of having high resistance to impact because the LED chip 202 is firmly mounted by fusion bonding by laser irradiation.

<Second Embodiment> In this embodiment, an example using a laser processing device 300 having a structure different from that of the first embodiment will be described. Specifically, the laser processing apparatus 300 of this embodiment includes the second workpiece unit 320 that holds the element substrate 200 by electrostatic adsorption. In addition, in the drawings, the same elements as those in the first embodiment are denoted by the same symbols, and repeated explanations are omitted.

FIG. 15 is a diagram showing the structure of the second workpiece unit 320 in the laser processing apparatus 300 used in the manufacturing method of the display device 10 of the second embodiment. Specifically, FIG. 15 corresponds to a view of the second workpiece unit 320 as viewed from the side holding the object to be processed. In addition, in FIG. 10 , the light shield 42 is arranged at the front of the second workpiece unit 320 . Therefore, for convenience of explanation, illustration of a part of the light shield 42 is omitted.

As shown in FIG. 15 , the holding member 35 has a treatment area 36 and an adsorption area 37 . The processing area 36 is an area for irradiating the device substrate 200, which is the object to be processed, with the laser light 320b (see FIG. 8). The holding member 35 holds the element substrate 200 by electrostatically adsorbing the semiconductor substrate 201 of the element substrate 200 to the holding surface 35a. At this time, similarly to the first embodiment, the plurality of LED chips 202 provided on the element substrate 200 are configured to be accommodated inside the processing area 36 . In addition, like the first embodiment, the holding member 35 is made of, for example, glass, quartz, sapphire, or the like.

The adsorption area 37 is an area used to electrostatically adsorb the component substrate 200 . As shown in FIG. 15 , internal electrodes 37 a and 37 b are provided inside the holding member 35 . That is, in a plan view, the area of the holding surface 35 a that overlaps the internal electrodes 37 a and 37 b corresponds to the adsorption area 37 . The adsorption area 37 is provided to surround the processing area 36 . That is, when the element substrate 200 is held by the holding member 35, since the plurality of LED chips 202 do not overlap the internal electrodes 37a and 37b, the internal electrodes 37a and 37b do not block the optical path of the laser light 320b.

In this embodiment, for example, a positive voltage is applied to the internal electrode 37a and a negative voltage is applied to the internal electrode 37b. Thereby, the internal charge of the object to be processed is polarized and attracted to the holding member 35 . That is, the second workpiece unit 320 of this embodiment holds the object to be processed (for example, the element substrate 200) by the electrostatic force generated between the holding member 35 and the object to be processed.

As shown in FIG. 15 , the plurality of openings 42 a of the light shield 42 are arranged inside the processing area 36 . That is, the portion of the light shield 42 that is actually used as a photomask is located inside the processing area 36 . In this embodiment, the light shield 42 is made of a metal film. At this time, if the film thickness of the light shield 42 is sufficiently thin, it will hardly affect the electrostatic force generated between the holding member 35 and the object to be processed. In this embodiment, by setting the film thickness of the light shield 42 to about several microns, electrostatic adsorption through the light shield 42 is possible.

In this embodiment, the case where the shape of the internal electrodes 37a and 37b is a semicircular shape in plan view is exemplified, but the invention is not limited to this example. The shape of the internal electrodes 37a and 37b may be a polygonal shape in plan view or an elliptical shape. In addition, the number of electrodes provided inside the holding member 35 is not limited to two, and may be three or more.

As described above, the laser processing apparatus 300 of this embodiment includes the second workpiece unit 320 in which the holding member 35 and the light shield 42 are integrated, and has a structure in which the laser light 320b is irradiated to the object to be processed through the holding member 35. When the laser processing apparatus 300 of this embodiment is used, since there is no gap between the light shield 42 and the object to be processed (the device substrate 200 in this embodiment), it is possible to prevent the light shield 42 from passing through the opening. Diffraction of laser light in part 42a.

<Third Embodiment> In the first embodiment and the second embodiment, the example in which the LED chip 202 is directly transferred from the element substrate 200 to the circuit substrate 100 is shown, but the invention is not limited to this example. Specifically, the LED chip 202 included in the element substrate 200 may be temporarily transferred to the carrier substrate, and then transferred from the carrier substrate to the circuit substrate 100 . In this case, when the terminal electrodes 203 of each LED chip 202 and the connection electrodes 103 of the circuit board 100 are fusion-joined, the laser processing apparatus 300 described in the first embodiment and the second embodiment can also be used.

<Fourth Embodiment> In the first embodiment and the second embodiment, the example in which the object to be processed (element substrate 200) is held using the adsorption force of the holding member is shown, but the invention is not limited to this example. For example, instead of adsorption, a method of mechanically holding the object to be processed with claws or the like, or a method of holding the object to be processed by adhesion using an adhesive or an adhesive sheet may be used. That is, as long as the holding member does not hinder the laser irradiation process, the object to be processed can be held in any way.

<Fifth Embodiment> In the first embodiment and the second embodiment, the holding member and the light shielding cover are shown as different members, but the invention is not limited to this example. For example, as the second workpiece unit, a structure in which the holding member and the light shield are integrally formed may be used. For example, a region that functions as a light shield may be formed by adding a black substance such as black pigment or carbon black to the holding surface of the holding member made of glass, quartz, sapphire, or the like.

The above-described embodiments as embodiments of the present invention can be appropriately combined and implemented within the scope of not contradicting each other. Based on each embodiment, those skilled in the art may appropriately add, delete, or change structural elements, or add, omit, or change conditions, as long as the gist of the present invention is maintained, they are all included in the scope of the present invention.

In addition, any other effects that are different from those obtained by the above-described embodiments, if they are clear from the description of this specification or can be easily predicted by those familiar with the art, should of course be interpreted as being predictable. obtained by this invention.

10:Display device 11:Insulating substrate 12: Semiconductor layer 13: Gate insulation layer 14: Gate electrode 15:Insulation layer 16: Source electrode 17: Drain electrode 18:Wiring 19: Planarization layer 20:Connect wiring 21:Insulation layer 22:Anode electrode 23:Cathode electrode 24: Planarization layer 25a:Mounting pad 25b:Mounting pad 30:Keep components 30a:Maintenance surface 31: Processing area 32: Adsorption area 32a: Adsorption hole 35: Maintain components 35a:Maintenance surface 36: Processing area 37: Adsorption area 37a: Internal electrode 37b: Internal electrode 40: Lens hood 40a: opening 40b: Adsorption hole 42: Lens hood 42a: opening 50:Laser light 60:Laser light 70:Keep components 100:Circuit substrate 101:Substrate 102:Drive circuit 103: Connect the electrode 103a: Connect electrode 103b: Connect electrode 110: pixels 110B: pixel 110G:pixel 110R:pixel 112:Display area 114: Surrounding area 116:Terminal area 120:Pixel circuit 120B: Pixel circuit 120G: Pixel circuit 120R: Pixel circuit 121:Data line 122: Gate line 123:Anode power cord 124:Cathode power cord 126: Select transistor 127: Driving transistor 128: Holding capacitor 129:LED 130: Data drive circuit 140: Gate drive circuit 150:Terminal part 151:Connect wiring 152:Connect wiring 160: Flexible printed circuit substrate 170:IC chip 200:Substrate 201:Semiconductor substrate 202:LED chip 202B:LED chip 202G:LED chip 202R:LED chip 203a:Terminal electrode 203b:Terminal electrode 203R:Terminal electrode 300:Laser processing device 302:Laser oscillator 304:Reflector 306: Beam expander 308: 1st workpiece unit 310: 2nd workpiece unit 320: 2nd workpiece unit 320a:Laser light 320b:Laser light D1: direction D2: direction S11: Steps S12: Steps S13: Steps

FIG. 1 is a flowchart showing the manufacturing method of the display device according to the first embodiment. FIG. 2 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 3 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 4 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 5 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 6 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 7 is a cross-sectional view showing the manufacturing method of the display device according to the first embodiment. FIG. 8 is a diagram showing the structure of a laser processing device used in the manufacturing method of a display device according to the first embodiment. FIG. 9 is a diagram showing the use of a laser processing device to perform a laser light irradiation process. FIG. 10 is a diagram showing the structure of the second workpiece unit of the laser processing apparatus used in the manufacturing method of the display device according to the first embodiment. FIG. 11 is a plan view showing the schematic structure of the display device according to the first embodiment. FIG. 12 is a block diagram showing the circuit configuration of the display device according to the first embodiment. FIG. 13 is a circuit diagram showing the structure of the pixel circuit of the display device according to the first embodiment. FIG. 14 is a cross-sectional view showing the pixel structure of the display device according to the first embodiment. FIG. 15 is a diagram showing the structure of the second workpiece unit of the laser processing apparatus used in the manufacturing method of the second embodiment.

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S13: Steps

Claims (7)

A method of manufacturing a display device, which includes the following steps: preparing a first substrate provided with a plurality of LED chips; and placing the plurality of LED chips so that the plurality of LED chips are located between the first substrate and the second substrate. is disposed on the second substrate; a part of the plurality of LED chips is irradiated with laser light through a light shield fixed to the holding member holding the first substrate; and the light shield is disposed close to the holding member. One side of the first substrate is in close contact with the first substrate; the holding member and the light shield each have an adsorption hole, and the holding member holds the above by vacuum suction through the adsorption holes provided in the holding member and the light shield. The first substrate; the laser light passes through the holding member and the opening formed in the light shield. The manufacturing method of a display device according to claim 1, wherein the laser light irradiates a part of the plurality of LED chips through the holding member. The method for manufacturing a display device according to claim 1, wherein when the first substrate is held on the holding member, in a plan view, the plurality of LED chips do not overlap with the adsorption holes provided on the holding member. The manufacturing method of the display device of claim 1 or 2, wherein the irradiation of the laser light includes Scan the linear laser light on the above-mentioned light shield. The manufacturing method of a display device according to claim 1 or 2, wherein the laser light is a fundamental wave or a second higher harmonic wave of a solid-state laser. The manufacturing method of a display device according to claim 1 or 2, wherein the laser light is near-infrared light; and the holding member is made of glass, quartz, or sapphire. The manufacturing method of a display device according to claim 6, wherein the connection electrode on the second substrate is bonded to the terminal electrode in a part of the plurality of LED chips by irradiation with the laser light.