LED chip and LED display

Abstract

This LED chip includes: an LED formation layer including a plurality of LEDs; a drive circuit formation layer electrically connected to each of the plurality of LEDs and including a drive circuit that controls each of the plurality of LEDs; a rewiring layer including wiring electrically connected to the drive circuit; and an electrode in contact with the rewiring layer and electrically connected to the wiring. The LED formation layer is positioned on a first surface of the drive circuit formation layer, and the rewiring layer is positioned on a second surface of the drive circuit formation layer opposite to the first surface.

Description

LED Chip and LED Display 【0001】 One embodiment of the present invention relates to an LED chip on which a plurality of light-emitting diodes (LEDs) are formed. Another embodiment of the present invention relates to an LED display on which a plurality of LED chips are mounted on a backplane. 【0002】 In small and medium-sized displays such as smartphones, displays using liquid crystals or OLEDs (Organic Light Emitting Diodes) have already been commercialized. In particular, an OLED display using an organic light-emitting element has advantages such as high contrast and no need for a backlight compared to a liquid crystal display. However, if an OLED display is continuously used at a high brightness, there is a problem that the brightness is significantly reduced. 【0003】 In recent years, as a next-generation display, the development of so-called micro-LED displays or mini-LED displays in which tiny LED chips are mounted on the pixels of a backplane has been promoted (for example, Patent Document 1). An LED is a self-emitting element similar to an OLED, but unlike an OLED, it is composed of an inorganic compound containing gallium (Ga) or indium (In). Therefore, compared with an OLED display, a micro-LED display is likely to ensure high reliability. In addition, an LED has higher luminous efficiency and brightness than an OLED. Therefore, a micro-LED display is expected as a next-generation display with high reliability, high brightness, and high contrast. 【0004】 Japanese Patent Publication No. 2019-511838 【0005】Augmented reality (AR) is a technology that overlays a virtual world onto the real world, and for displays used in headsets (i.e., head-mounted displays), there is a demand for small displays with high resolution. As mentioned above, while microLED displays have excellent visibility due to their high brightness and high contrast, small microLED displays suffer from reduced driving capability due to the narrow wiring width. In addition, the manufacturing of microLED displays requires implementation to electrically connect the microLEDs to the backplane, which presents a problem in that it makes it difficult to achieve high resolution. 【0006】 One embodiment of the present invention aims to provide an LED chip that has high driving capability and is easy to mount on a backplane. Another embodiment of the present invention aims to provide an LED display with high resolution. 【0007】 An LED chip according to one embodiment of the present invention includes an LED forming layer containing a plurality of LEDs, a drive circuit forming layer electrically connected to each of the plurality of LEDs and containing a drive circuit that controls each of the plurality of LEDs, a rewiring layer containing wiring electrically connected to the drive circuit, and electrodes in contact with the rewiring layer and electrically connected to the wiring, wherein the LED forming layer is located on a first surface of the drive circuit forming layer, and the rewiring layer is located on a second surface opposite to the first surface of the drive circuit forming layer. 【0008】An LED display according to one embodiment of the present invention includes a plurality of LED chips and a backplane including a plurality of pixels on which each of the plurality of LED chips is mounted, each of the plurality of LED chips includes an LED forming layer including a plurality of LEDs, a drive circuit forming layer including a drive circuit electrically connected to each of the plurality of LEDs and controlling each of the plurality of LEDs, a redistribution layer including wiring electrically connected to the drive circuit, and an electrode in contact with the redistribution layer and electrically connected to the wiring, the LED forming layer is located on a first surface of the drive circuit forming layer, the redistribution layer is located on a second surface opposite to the first surface of the drive circuit forming layer, and the backplane includes, for each of the plurality of pixels, a bump electrically connected to the electrode, a selection transistor electrically connected to the bump, and a signal line electrically connected to the selection transistor and inputting a data signal to the selection transistor. 【0009】This is a schematic plan view showing the configuration of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of the LED chip and backplane of an LED display according to one embodiment of the present invention. This is a schematic top view showing the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a schematic top view showing the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a schematic top view showing the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a schematic bottom view showing the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a schematic bottom view showing the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a flowchart illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the manufacturing method of an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view illustrating the configuration of the LED chip mounted on an LED display according to one embodiment of the present invention. This is a schematic cross-sectional view showing the configuration of an LED chip implemented in an LED display according to one embodiment of the present invention. 【0010】Embodiments of the present invention will be described below with reference to the drawings. The following disclosure is merely an example. Configurations that a person skilled in the art could easily conceive by appropriately modifying the configuration of the embodiments while maintaining the spirit of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment. However, the illustrated shapes are merely examples and do not limit the interpretation of the present invention. In this specification and drawings, components similar to those described above with respect to previously shown figures are denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate. 【0011】 In this specification, for the sake of explanation, the terms "up" or "above" or "down" or "below" will be used. However, as a general rule, the substrate on which the structure is formed is used as the reference point, and the direction from the substrate toward the structure is defined as "up" or "above." Conversely, the direction from the structure toward the substrate is defined as "down" or "below." Therefore, in the expression "structure on a substrate," the surface of the structure facing the substrate is the bottom surface of the structure, and the opposite surface is the top surface of the structure. Furthermore, the expression "structure on a substrate" merely describes the hierarchical relationship between the substrate and the structure, and other components may be placed between the substrate and the structure. In addition, the terms "up" or "above" or "down" or "below" refer to the stacking order in a structure with multiple layers, and do not necessarily mean that the layers are in a superimposed positional relationship in a plan view. 【0012】 In this specification, the expressions "α includes A, B, or C," "α includes any one of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A through C unless otherwise specified. Furthermore, these expressions do not exclude cases where α includes other components. 【0013】 [1. Configuration of the LED display 10] An LED display 10 according to one embodiment of the present invention will be described with reference to Figure 1. 【0014】Figure 1 is a schematic plan view showing the configuration of an LED display 10 according to one embodiment of the present invention. 【0015】 As shown in Figure 1, the LED display 10 includes a plurality of LED chips 100 and a backplane 200. A display unit DP is provided in the central region of the backplane 200, and a peripheral region surrounds the display unit DP. In the display unit DP, a plurality of pixels Px are arranged in a matrix. The LED chips 100 are mounted on the backplane 200 for each of the plurality of pixels Px. In addition, a scan line drive circuit GDr and a signal line drive circuit SDr are provided in the peripheral region of the backplane 200. In other words, the scan line drive circuit GDr and the signal line drive circuit SDr are provided outside the display unit DP. The scan line drive circuit GDr is electrically connected to a plurality of scan lines GL extending in the x direction within the display unit DP. The signal line drive circuit SDr is electrically connected to a plurality of signal lines SL extending in the y direction, which is perpendicular to the x direction, within the display unit DP. The control signals generated in the scan line drive circuit GDr are input to the plurality of scan lines GL. Similarly, the data signals generated in the signal line drive circuit SDr are input to multiple signal lines SL. 【0016】 Each of the multiple pixels Px is provided with a selection transistor Tr within the backplane 200. The selection transistor Tr is electrically connected to the scan line GL and the signal line SL, and its ON or OFF state is controlled by the control signal of the scan line GL. The selection transistor Tr is also electrically connected to the LED chip 100. When the selection transistor Tr is ON, the data signal from the signal line SL is input to the LED chip 100. 【0017】Figure 1 shows a configuration in which one pixel Px is provided with one selection transistor Tr, and a data signal is input from one signal line SL via the selection transistor Tr. However, the configuration of the pixel Px and the signal line SL are not limited to this. Multiple selection transistors Tr may be provided for one pixel Px, and multiple signal lines SL may be provided that are electrically connected to each of the multiple selection transistors Tr so that multiple data signals are input to one pixel Px. 【0018】 Although not shown in the diagram, the LED chip 100 is electrically connected to power lines provided on the backplane 200. Therefore, the LED chip 100 is supplied with a high-potential power supply voltage VDD and a low-potential power supply voltage VSS. 【0019】 The LED display 10 is a so-called active matrix display. At the pixel Px where the scan line GL and the signal line SL intersect, a selection transistor Tr is controlled by the control signal of the scan line GL, and the data signal of the signal line SL is input to the LED chip 100. This makes it possible to control the light emission state (e.g., brightness and color) at the pixel Px. 【0020】 [2. Configuration of LED Chip 100 and Backplane 200] Referring to Figure 2, the LED chip 100 and backplane 200 of the LED display 10 according to one embodiment of the present invention will be described further. 【0021】 Figure 2 is a schematic cross-sectional view showing the configuration of the LED chip 100 and backplane 200 of an LED display 10 according to one embodiment of the present invention. 【0022】 As shown in Figure 2, the LED chip 100 includes an LED forming layer 110, a drive circuit forming layer 120, a redistribution layer 130, and electrodes 140. The LED forming layer 110 is provided on one surface of the drive circuit forming layer 120 (hereinafter referred to as the "first surface"). The redistribution layer 130 is provided on the other surface of the drive circuit forming layer 120 (hereinafter referred to as the "second surface"). The electrodes 140 are provided so as to be in contact with the redistribution layer 130. 【0023】In the LED forming layer 110, a red LED 111r, a green LED 111g, and a blue LED 111b are formed on the support substrate 113. For example, each of the red LED 111r, green LED 111g, and blue LED 111b has two connecting electrodes 112 (anode and cathode). The two connecting electrodes 112 are exposed from the surface of the LED forming layer 110. In this embodiment, a configuration in which the terminals of the LED 111 are formed on the same surface has been described, but the anode terminal and cathode terminal of the LED 111 may be arranged on different surfaces. For example, as in a vertical LED structure, the anode terminal may be formed on the surface facing the drive circuit forming layer 120, and the cathode terminal may be formed on the surface facing the support substrate 113, opposite to the drive circuit forming layer 120. 【0024】 The red LED 111r emits red light. The light-emitting layer of the red LED 111r contains, for example, aluminum, gallium, indium, and phosphorus. The composition ratio of aluminum, gallium, and indium is typically, but not limited to, aluminum:gallium:indium = 0.225:0.275:0.5. 【0025】 The green LED 111g emits green light. The light-emitting layer of the green LED 111g contains, for example, indium, gallium, and nitrogen. The composition ratio of indium to gallium is typically, but not limited to, indium:gallium = 0.30:0.70. 【0026】 The blue LED 111b emits blue light. The light-emitting layer of the blue LED 111b contains, for example, indium, gallium, and nitrogen. The composition ratio of indium to gallium is typically, but not limited to, indium:gallium = 0.15:0.85. 【0027】 In the following, when red LED 111r, green LED 111g, and blue LED 111b are not specifically distinguished, they may be described as LED 111. That is, the LED forming layer 110 contains multiple LEDs 111. 【0028】In the LED chip 100, the light emitted from the LED 111 passes through the support substrate 113 and is emitted to the outside. Therefore, the support substrate 113 is light-transmitting. For example, the support substrate 113 is a glass substrate, a quartz substrate, or a sapphire substrate, but is not limited to these. Also, if the connecting electrodes 112 are arranged on one surface as shown in Figure 2, the support substrate 113 may not be necessary. 【0029】 The drive circuit forming layer 120 includes a drive circuit 121, and connection electrodes 122 and 123 electrically connected to the drive circuit 121. As will be described in detail later, the drive circuit 121 can control each of the multiple LEDs 111 of the LED forming layer 110 based on data signals. In other words, the drive circuit 121 can control the light emission of each of the multiple LEDs 111 contained in a single pixel Px. For example, the drive circuit 121 includes a CMOS circuit and a memory circuit. The connection electrode 122 is exposed from a first surface and is electrically connected to the connection electrode 122 of the LED forming layer 110. The connection electrode 123 is exposed from a second surface and is electrically connected to the wiring 131 of the rewiring layer 130. The electrode 140 is also electrically connected to the wiring 131. 【0030】 The electrode 140 is a connecting electrode provided on the LED chip 100 side to electrically connect the LED chip 100 to the wiring formed on the backplane 200. The electrode 140 is formed on the redistribution layer 130. However, the configuration of the electrode 140 is not limited to this. The electrode 140 may be formed within the redistribution layer 130 such that the electrode 140 is exposed from the surface of the redistribution layer 130. The electrode 140 can be made of the same material as the wiring of the redistribution layer 130. The width of the electrode 140 is less than 10 μm, but the area of ​​the electrode 140 can be made larger than the area of ​​the connecting electrode 112. 【0031】 Furthermore, as shown in Figure 2, the backplane 200 includes a substrate 210, a pixel selection control circuit formation layer 220, and bumps 230. The pixel selection control circuit formation layer 220 is provided on the substrate 210. The bumps 230 are provided on the pixel selection control circuit formation layer 220. 【0032】The substrate 210 is used as the base material for the LED display 10. For example, the substrate 210 is a glass substrate, but is not limited to this. The substrate 210 may be a rigid substrate such as a quartz substrate, or a flexible substrate such as a polyimide substrate. 【0033】 The pixel selection control circuit formation layer 220 has a scan line GL, a signal line SL, a scan line drive circuit GDr, and a signal line drive circuit SDr formed on it. In Figure 2, the selection transistor Tr is formed on the pixel selection control circuit formation layer 220, but the selection transistor Tr does not have to be formed on the pixel selection control circuit formation layer 220. In this case, the selection transistor Tr is formed on the drive circuit formation layer 120. 【0034】 The bump 230 is a connecting electrode provided on the backplane 200 side for electrically connecting the LED chip 100 to the backplane 200. The bump 230 is formed to protrude from the surface of the pixel selection control circuit forming layer 220. For example, the bump 230 is a gold bump, solder bump, copper pillar bump, or gold stud bump, but is not limited to these. The bump 230 may be formed by plating or by screen printing. The area of ​​the bump 230 is larger than the area of ​​the connecting electrode 112. 【0035】 When the LED chip 100 is mounted on the backplane and the electrodes 140 are joined to the bumps 230, the LED chip 100 and the backplane 200 are electrically connected. Therefore, when a data signal is input to the drive circuit 121, the drive circuit 121 calculates the emission period of the red LED 111r, green LED 111g, and blue LED 111b based on the data signal, and controls the emission of each of the red LED 111r, green LED 111g, and blue LED 111b. This makes it possible to control the brightness and emission color of the pixel Px. 【0036】 Furthermore, with reference to Figures 3 to 7, an LED chip 100 mounted on an LED display 10 according to one embodiment of the present invention will be described. Here, the arrangement of the LEDs 111 and electrodes 140 of the LED chip 100 will be described. 【0037】 Figures 3 to 5 are schematic top views showing the configuration of an LED chip 100 mounted on an LED display 10 according to one embodiment of the present invention. In Figures 3 to 5, for the sake of explanation, the LED 111 located below the support substrate 113 is shown by a dotted line. 【0038】 In the LED arrangement shown in Figure 3, the red LED 111r, green LED 111g, and blue LED 111b are arranged in order in the x-direction. The order of the red LED 111r, green LED 111g, and blue LED 111b is not particularly limited. 【0039】 In the LED arrangement shown in Figure 4, a red LED 111r is at the center, with green LEDs 111g positioned adjacent to it in the x-direction, and a blue LED 111b positioned adjacent to it in the y-direction. That is, the red LED 111r, green LED 111g, and blue LED 111b are arranged in an L-shape. Note that the LED 111 positioned at the center may be either a green LED 111g or a blue LED 111b. 【0040】 In the LED arrangement shown in Figure 5, in addition to the LED arrangement shown in Figure 4, another red LED 111r is arranged. That is, two red LEDs 111r are arranged diagonally. Note that the two LEDs 111 may also be green LEDs 111g or blue LEDs 111b. 【0041】 As explained above with reference to Figures 3 to 5, the arrangement configuration of the multiple LEDs 111 included in the LED chip 100 is not particularly limited. Furthermore, the number of LEDs 111 is also not limited. 【0042】 Figures 6 and 7 are schematic bottom views showing the configuration of an LED chip 100 mounted on an LED display 10 according to one embodiment of the present invention. 【0043】FIG. 6 shows six electrodes 140 formed on the LED chip 100. Specifically, three electrodes 140 are arranged in two rows. For example, the six electrodes 140 can correspond to electrodes for supplying the respective data signals, logic voltages, and high-potential side power supply voltage VDD and low-potential side power supply voltage VSS of the drive circuit 121 of the red LED 111r, green LED 111g, and blue LED 111b. However, the functions of the six electrodes 140 are not limited to these. Also, the arrangement of the six electrodes 140 is not limited to the configuration shown in FIG. 6. 【0044】 FIG. 7 shows eight electrodes 140 formed on the LED chip 100. Specifically, the eight electrodes 140 are symmetrically arranged so as to correspond to the four vertices and four sides of a rectangle. For example, the eight electrodes 140 can correspond to electrodes for supplying the respective data signals, logic voltages, high-potential side power supply voltage VDD and low-potential side power supply voltage VSS of the drive circuit 121, and electrodes for inputting two systems of clock signals of the red LED 111r, green LED 111g, and blue LED 111b. However, the functions of the eight electrodes 140 are not limited to these. Also, the arrangement of the eight electrodes 140 is not limited to the configuration shown in FIG. 6. 【0045】 As shown in FIGS. 6 and 7, the number of electrodes 140 is not particularly limited. The number of electrodes 140 is appropriately determined according to the number of LED chips 100 of the electrodes 140 and the configuration of the drive circuit 121, that is, the input data signals, supplied power supply voltages, and the like. Also, the areas of the plurality of electrodes 140 may be the same or different. 【0046】In the LED chip 100, since the rewiring layer 130 is formed, the position of the electrode 140 can be freely arranged by routing the wiring 131 of the rewiring layer 130. In other words, the degree of freedom in arranging the electrode 140 is high, and the electrode 140 can be arranged according to the position of the bump 230 on the backplane 200. Also, the area of the electrode 140 can be set without being affected by the area of the connection electrode 112, and the area of the electrode 140 can be made larger or smaller than the area of the connection electrode 112. For example, when the area of the electrode 140 is made larger than the area of the connection electrode 112, even if the electrode 140 does not completely overlap with the bump 230, a sufficient voltage can be supplied to the drive circuit 121. 【0047】 [3. Manufacturing method of the LED display 10] Referring to FIGS. 8 to 12, a manufacturing method of the LED display 10 according to an embodiment of the present invention will be described. 【0048】 FIG. 8 is a flowchart for explaining a manufacturing method of the LED display 10 according to an embodiment of the present invention. FIGS. 9 to 12 are schematic cross-sectional views for explaining a manufacturing method of the LED display 10 according to an embodiment of the present invention. 【0049】 The flowchart shown in FIG. 8 includes steps S110 to S160. Hereinafter, each step will be described in order while appropriately referring to FIGS. 9 to 15. 【0050】 In step S110, the red LED 111r, the green LED 111g, and the blue LED 111b are taken as one LED unit, and a plurality of LED units are formed on a transparent support wafer 130W. The red LED 111r, the green LED 111g, and the blue LED 111b may be directly formed on the support wafer, or the separately manufactured red LED 111r, green LED 111g, and blue LED 111b may be transferred onto the support wafer 130W. The support wafer 130W is a wafer that serves as the support substrate 113. That is, in step S110, an LED wafer 1100 on which the LED formation layer 110 is formed is manufactured (see FIG. 9). The connection electrode 112 of the LED 111 is exposed on the surface of the LED wafer 1100. 【0051】 In step S120, the drive circuit 121 and the connecting electrode 122 are formed using the semiconductor wafer 1200 (see Figure 10). For example, the semiconductor wafer 1200 is a silicon wafer, but is not limited to this. 【0052】 In step S130, the LED wafer 1100 and the semiconductor wafer 1200 are directly bonded together (see Figure 11). In other words, wafer bonding is performed in step S130. This electrically connects the connection electrode 112 of the LED 111 on the LED wafer 1100 to the connection electrode 122 of the semiconductor wafer 1200. 【0053】 In step S140, a connecting electrode 123 is formed on the semiconductor wafer 1200 that is electrically connected to the drive circuit 121 (see Figure 12). 【0054】 In step S150, wiring 131 that is electrically connected to the connecting electrode 123 and electrode 140 that is electrically connected to the wiring 131 are formed on the semiconductor wafer 1200 (see Figure 13). 【0055】 In step S160, the bonded LED wafer 1100 and semiconductor wafer 1200 are diced to separate the LED chip 100 (see Figure 14). This creates an LED chip 100 including an LED formation layer 110, a drive circuit formation layer 120, a redistribution layer 130, and electrodes 140. 【0056】 In step S170, the LED chip 100 is mounted on the backplane 200 (see Figure 15). Specifically, the LED chip 100 is bonded to the backplane 200 so that the bumps 230 of the backplane 200 and the electrodes 140 of the LED chip 100 are electrically connected. This manufactures the LED display 10 shown in Figure 1. 【0057】 As another method for manufacturing the LED display 10, a red LED 111r, a green LED 111g, and a blue LED 111b may be mounted on a silicon substrate including a drive circuit formation layer 120 by a transfer process, a redistribution layer 130 may then be formed, and the silicon substrate may be etched to form a silicon chip. 【0058】 Furthermore, as yet another method for manufacturing the LED display 10, a redistribution layer 130 is formed on a silicon substrate including a drive circuit formation layer 120, and the silicon substrate is etched to form a silicon chip. Next, the silicon chip is mounted on a backplane 200 by a transfer process. After that, a red LED 111r, a green LED 111g, and a blue LED 111b may be transferred onto the silicon chip. 【0059】 In the LED display 10 according to this embodiment, the backplane 200 has only a pixel selection control circuit forming layer 220 for selecting pixels Px to emit light, and the drive circuit 121 for driving multiple LEDs 111 within a pixel Px is built into the LED chip 100. That is, the LED chip 100 includes not only multiple LEDs 111 that constitute one pixel Px, but also a drive circuit 121 that controls the multiple LEDs 111. In the LED chip, the drive circuit 121 formed using a semiconductor wafer 1200 has high driving capability and can control multiple LEDs 111 at high speed. In addition, since the LED chip 100 includes a redistribution layer 130, the area of ​​the electrodes 140 for electrical connection with the backplane 200 can be increased, and the distance between two adjacent electrodes 140 can be increased. As a result, it becomes easy to densely mount multiple LED chips 100 on the backplane 200, and a high-resolution LED display 10 can be manufactured. 【0060】 <Modification 1> Referring to Figure 16, an LED chip 100A, which is a modification of the LED chip 100, will be described. Note that when the LED chip 100A has the same components as the LED chip 100, the description of those components may be omitted. 【0061】 Figure 16 is a schematic cross-sectional view showing the configuration of an LED chip 100A mounted on an LED display 10 according to one embodiment of the present invention. 【0062】As shown in Figure 16, the LED chip 100A includes an LED forming layer 110A, a drive circuit forming layer 120, a redistribution layer 130, and electrodes 140. The LED forming layer 110A is provided on the first surface of the drive circuit forming layer 120. In the LED forming layer 110A, a blue LED 111b, a green LED 111g, and a red LED 111r are sequentially stacked on the support substrate 113. Since the LED forming layer 110A can directly form the blue LED 111b, green LED 111g, and red LED 111r on the support wafer corresponding to the support substrate 113, the production of LED wafers is easy. Therefore, the manufacturing cycle time of the LED chip 100A can be shortened and the manufacturing cost of the LED chip 100A can be suppressed. 【0063】 The LED chip 100A includes not only multiple LEDs 111 that constitute a single pixel Px, but also a drive circuit 121 that controls the multiple LEDs 111. In other words, the LED chip 100A has a drive circuit 121 formed using a semiconductor wafer 1200 that has high driving capability and can control the multiple LEDs 111 at high speed. Furthermore, because the LED chip 100A includes a redistribution layer 130, the area of ​​the electrodes 140 for electrical connection with the backplane 200 can be increased, and the distance between two adjacent electrodes 140 can be increased. As a result, it becomes easy to densely mount multiple LED chips 100A on the backplane 200, and a high-resolution LED display 10 can be manufactured. In particular, because multiple LEDs 111 are stacked in the LED chip 100A, the mounting area of ​​the LED chip 100A is small, and it is also possible to achieve even higher resolution. 【0064】 <Modification 2> Referring to Figure 17, another modification of LED chip 100, LED chip 100B, will be described. Note that if LED chip 100B has the same components as LED chip 100, the description of those components may be omitted. 【0065】 Figure 17 is a schematic cross-sectional view showing the configuration of an LED chip 100B mounted on an LED display 10 according to one embodiment of the present invention. 【0066】As shown in Figure 17, the LED chip 100B includes an LED formation layer 110B, a drive circuit formation layer 120, a redistribution layer 130, and electrodes 140. The LED formation layer 110B is provided on the first surface of the drive circuit formation layer 120. Three blue LEDs 111b are formed on the support substrate 113 in the LED formation layer 110. In addition, a color conversion layer 114 is formed on the back surface of the support substrate 113 (the surface opposite to the surface on which the blue LEDs 111b are formed). The color conversion layer 114 includes, for example, quantum dots with controlled particle size, and can convert the blue light emitted from the blue LEDs 111b into red or green light. Since the LED formation layer 110B can directly form only multiple blue LEDs 111b on the support wafer corresponding to the support substrate 113, the fabrication of the LED wafer is easy. Therefore, the manufacturing cycle time of the LED chip 100B can be shortened and the manufacturing cost of the LED chip 100B can be suppressed. 【0067】 The LED chip 100B includes not only multiple LEDs 111 that constitute a single pixel Px, but also a drive circuit 121 that controls the multiple LEDs 111. In other words, the LED chip 100B has a drive circuit 121 formed using a semiconductor wafer 1200 that has high driving capability and can control the multiple LEDs 111 at high speed. Furthermore, because the LED chip 100B includes a redistribution layer 130, the area of ​​the electrodes 140 for electrical connection with the backplane 200 can be increased, and the distance between two adjacent electrodes 140 can be increased. As a result, it becomes easy to densely mount multiple LED chips 100B on the backplane 200, making it possible to manufacture an LED display 10 with high resolution. 【0068】 The embodiments and modifications described above as embodiments of the present invention can be combined as appropriate, insofar as they do not contradict each other. Furthermore, configurations in which a person skilled in the art has added, deleted, or modified components, or added, omitted, or modified processes, based on the embodiments and modifications, are also included in the scope of the present invention, as long as they retain the essence of the present invention. 【0069】Any effects or benefits other than those brought about by the embodiments and modifications described above, if they are clear from the description herein or easily predictable to a person skilled in the art, are naturally considered to be brought about by the present invention. 【0070】 10: LED display, 100, 100A, 100B: LED chip, 110, 110A, 110B: LED formation layer, 111: LED, 111r: Red LED, 111g: Green LED, 111b: Blue LED, 112: Connection electrode, 113: Support substrate, 114: Color conversion layer, 120: Drive circuit formation layer, 121: Drive circuit, 122: Connection electrode, 123: Connection electrode, 130: Redistribution layer, 131: Wiring, 140: Electrode, 200: Backplane, 210: Substrate, 220: Pixel selection control circuit formation layer, 230: Bump, 1100: LED wafer, 1200: Semiconductor wafer, DP: Display unit, Px: Pixel, Tr: Selection transistor, GDr: Scan line drive circuit, GL: Scan line, SDr: Signal line drive circuit, SL: Signal line

Claims

1. An LED chip comprising: an LED forming layer containing a plurality of LEDs; a drive circuit forming layer electrically connected to each of the plurality of LEDs and containing a drive circuit that controls each of the plurality of LEDs; a rewiring layer containing wiring electrically connected to the drive circuit; and electrodes in contact with the rewiring layer and electrically connected to the wiring, wherein the LED forming layer is located on a first surface of the drive circuit forming layer, and the rewiring layer is located on a second surface of the drive circuit forming layer opposite to the first surface.

2. The LED chip according to claim 1, wherein the plurality of LEDs include a red LED, a green LED, and a blue LED.

3. The LED chip according to claim 2, wherein the red LED, green LED, and blue LED are stacked.

4. The LED chip according to claim 1, wherein the plurality of LEDs includes a plurality of blue LEDs.

5. The LED chip according to claim 4, further comprising a light conversion layer in contact with the LED forming layer and for converting the color of light emitted from at least some of the plurality of blue LEDs.

6. The LED chip according to claim 1, wherein the LED forming layer further includes a support substrate on which the plurality of LEDs are formed, the drive circuit forming layer includes a semiconductor substrate on which the drive circuit is formed, and each of the plurality of LEDs is electrically connected to the drive circuit by direct bonding of the support substrate and the semiconductor substrate.

7. The LED chip according to claim 1, wherein the width of the electrode is less than 10 μm.

8. The LED chip according to claim 1, wherein each of the plurality of LEDs includes a connecting electrode for electrical connection to the drive circuit, and the area of ​​the electrode is greater than the area of ​​the connecting electrode.

9. An LED display comprising: a plurality of LED chips; a backplane including a plurality of pixels on which each of the plurality of LED chips is mounted; each of the plurality of LED chips comprising: an LED forming layer including a plurality of LEDs; a drive circuit forming layer including a drive circuit electrically connected to each of the plurality of LEDs and controlling each of the plurality of LEDs; a redistribution layer including wiring electrically connected to the drive circuit; and electrodes in contact with the redistribution layer and electrically connected to the wiring; the LED forming layer is located on a first surface of the drive circuit forming layer; the redistribution layer is located on a second surface opposite to the first surface of the drive circuit forming layer; and the backplane comprises: a bump electrically connected to the electrode at each of the plurality of pixels; a selection transistor electrically connected to the bump at each of the plurality of pixels; and a signal line electrically connected to the selection transistor and inputting a data signal to the selection transistor.

10. The LED display according to claim 9, wherein the plurality of LEDs include red LEDs, green LEDs, and blue LEDs.

11. The LED display according to claim 10, wherein the red LED, green LED, and blue LED are stacked.

12. The LED display according to claim 9, wherein the plurality of LEDs includes a plurality of blue LEDs.

13. The LED display according to claim 12, further comprising a light conversion layer in contact with the LED forming layer and for converting the color of light emitted from at least some of the plurality of blue LEDs.

14. The LED display according to claim 9, wherein the LED forming layer further includes a support substrate on which the plurality of LEDs are formed, the drive circuit forming layer includes a semiconductor substrate on which the drive circuit is formed, and each of the plurality of LEDs is electrically connected to the drive circuit by the direct bonding of the support substrate and the semiconductor substrate.

15. The LED display according to claim 9, wherein the width of the electrode is less than 10 μm.

16. The LED display according to claim 9, wherein each of the plurality of LEDs includes a connecting electrode for electrical connection to the drive circuit, and the area of ​​the electrode is greater than the area of ​​the connecting electrode.

17. The LED display according to claim 16, wherein the area of ​​the bump is larger than the area of ​​the connecting electrode.

18. The LED display according to claim 9, wherein the backplane includes a glass substrate, and the selected transistor is provided on the glass substrate.

Images