US-12628487-B2 - Image display device and method for manufacturing image display device

US12628487B2US 12628487 B2US12628487 B2US 12628487B2US-12628487-B2

Abstract

A method for manufacturing an image display device includes: preparing a substrate comprising a circuit and a first insulating film covering the circuit; forming a conductive layer on the first insulating film, the conductive layer comprising a single-crystal metal; forming a semiconductor layer on the conductive layer, the semiconductor layer comprising a light-emitting layer; forming a light-emitting element including a bottom surface on the conductive layer, and a light-emitting surface at a side opposite to the bottom surface; forming a second insulating film covering the conductive layer, light-emitting element, and first insulating film; forming a first via extending through the first and second insulating films; and forming a wiring layer on the second insulating film. The first via is located between the wiring layer and the circuit and electrically connects the wiring layer and the circuit. The light-emitting element is electrically connected to the circuit via the wiring layer.

Inventors

Hajime Akimoto

Assignees

NICHIA CORPORATION

Dates

Publication Date: 20260512
Application Date: 20230905
Priority Date: 20210317

Claims (20)

1 . A method for manufacturing an image display device, the method comprising: preparing a substrate, the substrate comprising a circuit and a first insulating film covering the circuit; forming a conductive layer on the first insulating film, the conductive layer comprising a single-crystal metal; forming a semiconductor layer on the conductive layer, the semiconductor layer comprising a light-emitting layer; forming a light-emitting element by etching the semiconductor layer, the light-emitting element including a bottom surface on the conductive layer, and a light-emitting surface at a side opposite to the bottom surface; forming a second insulating film covering the conductive layer, the light-emitting element, and the first insulating film; forming a first via extending through the first and second insulating films; and forming a wiring layer on the second insulating film; wherein: the first via is located between the wiring layer and the circuit and electrically connects the wiring layer and the circuit, the light-emitting element is electrically connected to the circuit via the wiring layer.
2 . The method according to claim 1 , wherein: the forming of the conductive layer includes: forming a metal layer on the first insulating film, and performing annealing treatment of the metal layer.
3 . The method according to claim 2 , wherein: the forming of the conductive layer includes, after the forming of the metal layer and before the annealing treatment of the metal layer, patterning the metal layer.
4 . The method according to claim 1 , further comprising: forming a second via extending through the second insulating film, the second via being located between the conductive layer and the wiring layer and electrically connecting the conductive layer and the wiring layer, wherein: the light-emitting element is connected to the circuit via the conductive layer, the second via, the wiring layer, and the first via.
5 . The method according to claim 1 , wherein: the substrate comprises a plug electrically connected to the circuit, and the conductive layer is formed on the plug and the first insulating film in the forming of the conductive layer.
6 . The method according to claim 1 , further comprising: before the forming of the semiconductor layer, forming, on the conductive layer, a layer comprising graphene.
7 . The method according to claim 1 , further comprising: exposing the light-emitting surface; and forming a light-transmitting electrode on the exposed light-emitting surface.
8 . The method according to claim 1 , wherein: the semiconductor layer comprises a gallium nitride compound semiconductor.
9 . The method according to claim 1 , further comprising: forming a wavelength conversion member on the light-emitting element.
10 . An image display device comprising: a circuit element; a first wiring layer electrically connected to the circuit element; a first insulating film covering the circuit element and the first wiring layer; a conductive layer located on the first insulating film, the conductive layer comprising a single-crystal metal; a light-emitting element located on the conductive layer and electrically connected to the conductive layer, the light-emitting element including a bottom surface on the conductive layer, and a light-emitting surface at a side opposite to the bottom surface; a second insulating film covering the conductive layer, the first insulating film, and a side surface of the light-emitting element; a second wiring layer located on the second insulating film; and a first via extending through the first and second insulating films, the first via being located between the first wiring layer and the second wiring layer and electrically connecting the first wiring layer and the second wiring layer, wherein: the light-emitting element is electrically connected to the circuit element via the first and second wiring layers.
11 . The image according to claim 10 , wherein: the conductive layer includes a first part including the single-crystal metal, the light-emitting element is located on the first part, and an outer perimeter of the light-emitting element is located within an outer perimeter of the first part when viewed in a plan view.
12 . The image according to claim 11 , further comprising: a second via provided to extend through the second insulating film, the second via being located between the first part and the second wiring layer and electrically connecting the first part and the second wiring layer, wherein: the light-emitting element is electrically connected to the circuit element via the first part, the second via, the second wiring layer, the first via, and the first wiring layer.
13 . The image according to claim 12 , further comprising: a third via extending through the second insulating film, wherein: the light-emitting element comprises: a first semiconductor layer of a first conductivity type, a light-emitting layer located on the first semiconductor layer, and a second semiconductor layer located on the light-emitting layer, the second semiconductor layer being of a second conductivity type, the second conductivity type being different from the first conductivity type, the first semiconductor layer, the light-emitting layer, and the second semiconductor layer are stacked in this order from the first part toward the light-emitting surface, the first semiconductor layer is located on the first part and electrically connected to the first part, the second wiring layer comprises: a first wiring part connected to the first and second vias, and a second wiring part connected to the light-emitting surface, the conductive layer comprises a third wiring part insulated from the first part, the third via is located between the third wiring part and the second wiring part and electrically connects the third wiring part and the second wiring part, the first semiconductor layer is connected to the circuit element via the first part, the second via, the first wiring part, the first via, and the first wiring layer, the second semiconductor layer is connected to the third wiring part via the second wiring part and the third via.
14 . The image according to claim 13 , wherein: the first conductivity type is a p-type, and the second conductivity type is an n-type.
15 . The image according to claim 11 , wherein: the first wiring layer comprises a fourth wiring part insulated from the first via, the image display device further comprises a plug located between the first part and the fourth wiring part, and the light-emitting element is electrically connected to the fourth wiring part via the first part and the plug.
16 . The image according to claim 10 , further comprising: a layer comprising graphene, located between the conductive layer and the light-emitting element.
17 . The image according to claim 10 , wherein: the second insulating film has an opening in which the light-emitting surface is exposed, and the image display device further comprises a light-transmitting electrode located on the light-emitting surface.
18 . The image according to claim 10 , wherein: the light-emitting element comprises a gallium nitride compound semiconductor.
19 . The image according to claim 10 , further comprising: a wavelength conversion member on the light-emitting element.
20 . An image display device comprising: a plurality of transistors; a first wiring layer electrically connected to the plurality of transistors; a first insulating film covering the plurality of transistors and the first wiring layer; a conductive layer located on the first insulating film, the conductive layer comprising a single-crystal metal; a semiconductor layer located on the conductive layer and electrically connected to the conductive layer, the semiconductor layer including a bottom surface on the conductive layer, and a plurality of light-emitting surfaces at a side opposite to the bottom surface; a second insulating film covering the first insulating film, the conductive layer, and a side surface of the semiconductor layer; a second wiring layer located on the second insulating film; and a via extending through the first and second insulating films, the via being located between the first wiring layer and the second wiring layer and electrically connecting the first wiring layer and the second wiring layer, wherein: the semiconductor layer is electrically connected to the plurality of transistors via the first and second wiring layers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a bypass continuation of PCT Application No. PCT/JP2022/010029, filed Mar. 8, 2022, which claims priority to Japanese Application No. 2021-043513, filed Mar. 17, 2021. The contents of these applications are hereby incorporated by reference in their entireties. BACKGROUND Embodiments of the invention relate to a method for manufacturing an image display device and an image display device. It is desirable to realize an image display device that is thin and has high luminance, a wide viewing angle, high contrast, and low power consumption. To satisfy such market needs, a display device that utilizes a self-luminous element is being developed. There are expectations for the advent of a display device that uses a micro LED that is a fine light-emitting element as a self-luminous element. A method has been introduced as a method for manufacturing a display device that uses a micro LED in which individually-formed micro LEDs are sequentially transferred to a drive circuit. However, as the number of elements of micro LEDs increases with higher image quality such as full high definition, 4K, 8K, etc., if many micro LEDs are individually formed and sequentially transferred to a substrate in which a drive circuit and the like are formed, an enormous amount of time is necessary for the transfer process. Also, there is a risk that connection defects between the micro LEDs, the drive circuits, etc., may occur, and a reduction of the yield may occur. In known technology, a semiconductor layer that includes a light-emitting layer is grown on a Si substrate; an electrode is formed at the semiconductor layer; subsequently, bonding is performed to a circuit board in which a drive circuit is formed (e.g., see Japanese Patent Publication No. 2002-141492). SUMMARY An embodiment of the invention provides a method for manufacturing an image display device in which a transfer process of a light-emitting element is shortened, and the yield is increased. A method for manufacturing an image display device according to an embodiment of the invention includes a process of preparing a substrate that includes a circuit and a first insulating film covering the circuit, a process of forming a conductive layer including a single-crystal metal on the first insulating film, a process of forming a semiconductor layer including a light-emitting layer on the conductive layer, a process of forming a light-emitting element by etching the semiconductor layer so that the light-emitting element includes a bottom surface on the conductive layer and includes a light-emitting surface that is a surface at a side opposite to the bottom surface, a process of forming a second insulating film covering the conductive layer, the light-emitting element, and the first insulating film, a process of forming a first via extending through the first and second insulating films, and a process of forming a wiring layer on the second insulating film. The first via is located between the wiring layer and the circuit and electrically connects the wiring layer and the circuit. The light-emitting element is electrically connected to the circuit via the wiring layer. An image display device according to an embodiment of the invention includes a circuit element, a first wiring layer electrically connected to the circuit element, a first insulating film covering the circuit element and the first wiring layer, a conductive layer that is located on the first insulating film and includes a single-crystal metal, a light-emitting element that is located on the conductive layer, is electrically connected to the conductive layer, includes a bottom surface on the conductive layer, and includes a light-emitting surface that is a surface at a side opposite to the bottom surface, a second insulating film covering the conductive layer, the first insulating film, and a side surface of the light-emitting element, a second wiring layer located on the second insulating film, and a first via provided to extend through the first and second insulating films. The first via is located between the first wiring layer and the second wiring layer and electrically connects the first wiring layer and the second wiring layer. The light-emitting element is electrically connected to the circuit element via the first and second wiring layers. An image display device according to an embodiment of the invention includes multiple transistors, a first wiring layer electrically connected to the multiple transistors, a first insulating film covering the multiple transistors and the first wiring layer, a conductive layer that is located on the first insulating film and includes a single-crystal metal, a semiconductor layer that is located on the conductive layer, is electrically connected to the conductive layer, includes a bottom surface on the conductive layer, and includes multiple light-emitting surfaces that are surfaces at a side opposite to t