Search

EP-3944343-B1 - METHOD FOR MANUFACTURING IMAGE DISPLAY DEVICE AND IMAGE DISPLAY DEVICE

EP3944343B1EP 3944343 B1EP3944343 B1EP 3944343B1EP-3944343-B1

Inventors

  • AKIMOTO, HAJIME

Dates

Publication Date
20260506
Application Date
20200319

Claims (20)

  1. A method for manufacturing an image display device, comprising: preparing a substrate (1194), the substrate (1194) including a semiconductor layer (1150), the semiconductor layer (1150) including a light emitting layer (1152), the semiconductor layer (1150) being grown on a first substrate (1001); wherein the method further comprises: bonding the semiconductor layer (1150) to a second substrate (1100), a circuit being formed on the second substrate (1100), the circuit including a circuit element (103, 103-1, 103-2) and a first interconnect layer (110, 310), the first interconnect layer (110, 310) includes multiple interconnects (110s, 110d, 310s, 310d1, 310d2) having different potentials which are connected to the circuit element (103, 103-1, 103-2), a first insulating film (112) covering the circuit element (103, 103-1, 103-2) and the first interconnect layer (110, 310) ; forming a light emitting element (150, 350) by etching the semiconductor layer (1150); forming a second insulating film (156, 356) covering the light emitting element (150, 350), the second insulating film (156, 356) being made of a black resin; forming a second interconnect layer (160, 360) electrically connected to the light emitting element (150, 350) and disposed on the second insulating film (156, 356), forming a first via (161d, 361d1, 361d2) extending through the first insulating film (112) and the second insulating film (156, 356), and electrically connecting the first interconnect layer (110, 310) and the second interconnect layer (160, 360); and electrically connecting the light emitting element (150, 350) and the circuit element (103, 103-1, 103-2) through the first via (161d, 361d1, 361d2), the first via (161d, 361d1, 361d2) connecting the light emitting element (150, 350) and the circuit element (103, 103-1, 103-2) to each other, the light emitting element (150, 350) and the circuit element (103, 103-1, 103-2) being provided in different layers; the first interconnect layer (110, 310) includes a first interconnect (110s, 310s) a portion including at least a part of the first interconnect (110s, 110d, 310s, 310d1, 310d2) is provided immediately below the light emitting element (150, 350), and an outer periphery of the portion includes an outer periphery of the light emitting element (150, 350) projected onto the portion in a plan view.
  2. The method for manufacturing the image display device according to claim 1, further comprising: removing the first substrate (1001) before bonding the semiconductor layer (1150) together the second substrate (1100).
  3. The method for manufacturing the image display device according to claim 1, further comprising: removing the first substrate (1001) after bonding the semiconductor layer (1150) together the second substrate (1100).
  4. The method for manufacturing the image display device according to claim 2, further comprising: exposing a surface of the light emitting element (150, 350).
  5. The method for manufacturing the image display device according to claim 4, further comprising: forming a transparent electrode (159a, 359a1, 359a2) on an exposed surface of the light emitting element (150, 350).
  6. The method for manufacturing the image display device according to claim 1, wherein the semiconductor layer (1150) is grown on a buffer layer (140) formed on the first substrate (1001).
  7. The method for manufacturing the image display device according to claim 6, wherein the buffer layer (140) includes a nitride.
  8. The method for manufacturing the image display device according to claim 1, wherein the first substrate (1001) includes silicon or sapphire.
  9. The method for manufacturing the image display device according to claim 1, wherein the semiconductor layer (1150) includes a gallium nitride-based compound semiconductor, and the second substrate (1100) includes silicon.
  10. The method for manufacturing the image display device according to claim 1, further comprising: forming a wavelength conversion member on the light emitting element (150, 350).
  11. An image display device, comprising: a circuit element (103, 103-1, 103-2); a first interconnect layer (110, 310) electrically connected to the circuit element (103, 103-1, 103-2); a first insulating film (112) covering the circuit element (103, 103-1, 103-2) and the first interconnect layer (110, 310), wherein the first interconnect layer (110, 310) includes multiple interconnects (110s, 110d, 310s, 310d1, 310d2) having different potentials; a light emitting element (150, 350) disposed on the first insulating film (112); a second insulating film (156, 356) covering at least a part of the light emitting element (150, 350) and being made of a black resin; a second interconnect layer (160, 360) including multiple electrically isolated interconnects (160a, 160k, 360a1, 360a2) which are electrically connected to the light emitting element (150, 350) and disposed on the second insulating film (156, 356); and a first via (161d, 361d1) extending through the first insulating film (112) and the second insulating film (156, 356), and electrically connecting the first interconnect layer (110, 310) and the second interconnect layer (160, 360), wherein the first interconnect layer (110, 310) includes a first interconnect (110s, 310s), a portion including at least a part of the first interconnect (110s, 310s) is provided immediately below the light emitting element (150, 350), and an outer periphery of the portion includes an outer periphery of the light emitting element (150, 350) projected onto the portion in a plan view.
  12. The image display device according to claim 11, wherein an opening (358-1, 358-2) exposing a light emission surface opposing a plane of the light emitting element (150, 350) on a side of the first insulating film (112) is includes, and a transparent electrode (359a) is provided on the light emission surface.
  13. The image display device according to claim 12, wherein an exposed surface exposed from the opening (358-1, 358-2) includes a rough surface.
  14. The image display device according to claim 11, further comprising: a buffer layer (140) between the first insulating film (112) and the light emitting element (150).
  15. The image display device according to claim 11, wherein the circuit element (103-1, 103-2) includes a transistor, the light emitting element (350) includes a first semiconductor layer (151, 353) of a first conductivity type, a second semiconductor layer (153, 351) of a second conductivity type being different from the first conductivity type, and a light emitting layer (152, 352) provided between the first semiconductor layer (151, 353) and the second semiconductor layer (153, 351), the first semiconductor layer (151, 353), the light emitting layer (152, 352), and the second semiconductor layer (153, 351) being stacked in this order from the first insulating film (112) toward the second interconnect layer (160,360), the first interconnect layer (110, 310) includes a second interconnect (110d, 310d1, 310d2) connected to a first main electrode of the transistor, the second interconnect layer (160, 360) includes a third interconnect (160a, 360a1, 360a2) connected to the first semiconductor layer (151, 353), one end of the first via (161d, 361d1, 361d2) is connected to the second interconnect (110d, 310d1, 310d2), and another end of the first via (161d, 361d1, 361d2) is connected to the third interconnect (160a, 360a1, 360a2).
  16. The image display device according to claim 15, further comprising: a second via (360a1, 360a2) extending through the second insulating film (156, 356), one end of the second via (360a1, 360a2) is connected to the first semiconductor layer (151, 353), and another end of the second via (360a1, 360a2) is connected to the third interconnect (160a, 360a1, 360a2).
  17. The image display device according to claim 15, wherein the first conductivity type is a p-type, the second conductivity type is an n-type, and the transistor is a p-type channel transistor.
  18. The image display device according to claim 15, wherein the first conductivity type is an n-type, the second conductivity type is a p-type, and the transistor is an n-type channel transistor.
  19. The image display device according to claim 11, wherein the light emitting element includes a gallium nitride-based compound semiconductor, and the circuit element is formed on a substrate, the substrate including silicon.
  20. The image display device according to claim 11, further comprising: a wave conversion member on the light emitting element.

Description

[Technical Field] Embodiments of the invention relate to a method for manufacturing an image display device and the image display device. [Background Art] It is desired to realize a thin image display device with high luminance, wide viewing angle, high contrast and low power consumption. In order to respond to such market demand, development of a display device using a self-light emitting element is in progress. The appearance of a display device using a micro LED, which is a fine light emitting element, is expected as a self-light emitting element. As a method for manufacturing a display device using micro LEDs, a method of sequentially transferring individually formed micro LEDs to a drive circuit has been introduced. However, as the number of micro LED elements increases as the image quality increases to full HD, 4K, 8K, etc., a large number of micro LEDs are individually formed and sequentially transferred to the substrate on which the drive circuit and the like are formed. An enormous amount of time is required for the transfer process. In addition, poor connection between the micro LED and the drive circuit or the like may occur, resulting in a decrease in yield. A technique is known in which a semiconductor layer including a light emitting layer is grown on a Si substrate, electrodes are formed on the semiconductor layer, and then bonded to a circuit substrate on which a drive circuit is formed (for example, JP 2002-141492 A (Kokai)). WO2018132070 A1 discloses a method comprising providing a first wafer comprising first layers disposed over a first substrate; providing a second partially processed wafer comprising silicon-based CMOS (Complementary Metal Oxide Semiconductor) devices formed in second layers disposed over a second substrate; and bonding the first and second wafers to form a composite wafer via a double-bonding transfer process. EP3336831A2 discloses a light emitting diode display device includes a plurality of subpixels (SP1) which each include first to Nth (where N is a natural number equal to or greater than two) light emitting diode devices (300a, 300b) emitting light with the data current and a pixel circuit (PC) including first to Nth driving transistors (Tdr1, Tdr2) respectively supplying the data current corresponding to a data signal to the first to Nth light emitting diode devices. EP3316303A1 discloses a display device comprises a first LED coupled with an input node, and further comprises pixel driver circuitry. The pixel driver circuitry comprises a data input transistor configured to conduct, based on a first control signal, a data signal across a first channel having a first channel W/L ratio. CN109285843A discloses a display device includes a substrate, a first pixel circuit, a second pixel circuit, a third pixel circuit, a protective layer, a first conductive structure, a second conductive structure, a third conductive structure, a plurality of first light emitting diodes, and a plurality of Two light emitting diodes and a plurality of third light emitting diodes. US 2018 0122788 A1 discloses a light emitting diode with an extending electrode on the sidewall of the semiconductor structure, electrically connected to the second electrode, to increase the contact area of electrical connection and improve current flow [Summary of Invention] [Problem to be Solved by Invention] The embodiments provide a method of manufacturing an image display device and an image display device that shorten the transfer process of the light emitting elements and improve the yield. [Means for Solving Problem] The above problem is solved by the subject matter of the independent claims. Further aspects of the subject matter is described in the sub claims. According to one embodiment not encompassed by the wording of the claims, a method for manufacturing an image display device is disclosed. The method can include preparing a substrate including a semiconductor layer. The semiconductor layer includes a light emitting layer. The semiconductor layer is grown on a first substrate. The method can include bonding the semiconductor layer together a second substrate. A circuit is formed on the second substrate, and includes a circuit element. The method can include forming a light emitting element by etching the semiconductor layer, forming an insulating film covering the light emitting element, and forming a via reaching the circuit through the insulating film. Additionally, the method can include electrically connecting the light emitting element and the circuit element through the via, the light emitting element and the circuit element on a side of a plane of the light emitting element, the plane opposing a plane on a side of the second substrate. The via connects the light emitting element and the circuit element to each other. The light emitting element and the circuit element are provided in different layers. According to one embodiment not encompassed by the wording of the claims, an image displ