US-12622205-B2 - Display device and method of manufacturing the same

Abstract

A display device includes a thin-film transistor, a source/drain electrode and an auxiliary electrode including a first conductive layer and a second conductive layer disposed on the first conductive layer, a via insulating layer having a first opening exposing the auxiliary electrode, a capping layer covering a portion of the auxiliary electrode and a light emitting material layer and a common electrode layer sequentially stacked on the via insulating layer and the capping layer, wherein the source/drain electrode is electrically connected to the thin-film transistor through a contact hole penetrating the interlayer insulating layer, the auxiliary electrode has an undercut, and the capping layer includes a first capping layer covering side surfaces of the first conductive layer of the auxiliary electrode and a second capping layer separated from the first capping layer and disposed on the second conductive layer of the auxiliary electrode.

Inventors

• Joon Gu LEE
• HYE JIN GWARK
• Jae Ik Kim
• Hwi Kim
• Jung Sun PARK
• Yeon Hwa LEE

Assignees

• SAMSUNG DISPLAY CO., LTD.

Dates

Publication Date

20260505

Application Date

20230620

Priority Date

20220928

Claims (17)

1. 1 . A display device comprising: a thin-film transistor disposed on a substrate; an interlayer insulating layer disposed on the thin-film transistor, a source/drain electrode and an auxiliary electrode that are formed as a same layer disposed on the interlayer insulating layer, each of the source/drain electrode and the auxiliary electrode comprising: a first conductive layer, and a second conductive layer disposed on an upper surface of the first conductive layer, a via insulating layer disposed on the interlayer insulating layer and the source/drain electrode, the via insulating layer including a first opening exposing the auxiliary electrode; a capping layer covering at least a portion of the auxiliary electrode; and a light emitting material layer and a common electrode layer sequentially stacked on an upper surface of the via insulating layer and an upper surface of the capping layer, wherein the source/drain electrode is electrically connected to the thin-film transistor through a contact hole penetrating the interlayer insulating layer, the auxiliary electrode has an undercut shape in which side surfaces of the first conductive layer of the auxiliary electrode are disposed inside side surfaces of the second conductive layer of the auxiliary electrode, and the capping layer comprises: a first capping layer covering the side surfaces of the first conductive layer of the auxiliary electrode, a second capping layer separated from the first capping layer and disposed on an upper surface of the second conductive layer of the auxiliary electrode, and the capping layer comprises a conductive material.
2. 2 . The display device of claim 1 , further comprising: a pixel electrode layer disposed between the via insulating layer and each of the capping layer and the light emitting material layer, wherein the pixel electrode layer comprises: a pixel electrode electrically connected to the source/drain electrode through a contact hole penetrating the via insulating layer; a first dummy pixel electrode separated from the pixel electrode and disposed on the first capping layer, and a second dummy pixel electrode separated from the first dummy pixel electrode and disposed on the second capping layer.
3. 3 . The display device of claim 2 , wherein the light emitting material layer comprises: a first portion disposed on the first dummy pixel electrode; and a second portion separated from the first portion of the light emitting material layer and disposed on the second dummy pixel electrode.
4. 4 . The display device of claim 3 , wherein the common electrode layer comprises: a first portion disposed on the first portion of the light emitting material layer and directly contacting the first capping layer; and a second portion separated from the first portion of the common electrode layer and disposed on the second portion of the light emitting material layer.
5. 5 . The display device of claim 1 , further comprising: a pixel electrode disposed on the via insulating layer and electrically connected to the source/drain electrode through a contact hole penetrating the via insulating layer, wherein the capping layer and the pixel electrode are formed of a same material.
6. 6 . The display device of claim 5 , wherein the light emitting material layer comprises: a first portion disposed on the first capping layer, and a second portion separated from the first portion of the light emitting material layer and disposed on the second capping layer.
7. 7 . The display device of claim 1 , wherein the auxiliary electrode further comprises a third conductive layer disposed between the first conductive layer of the auxiliary electrode and the interlayer insulating layer, and the side surfaces of the first conductive layer of the auxiliary electrode are disposed inside side surfaces of the third conductive layer of the auxiliary electrode.
8. 8 . The display device of claim 7 , wherein a thickness of the first capping layer covering the side surfaces of the first conductive layer decreases as the first capping layer is closer to the second conductive layer.
9. 9 . The display device of claim 8 , wherein a bottom surface of the second conductive layer of the auxiliary electrode comprises a surface exposed from the first conductive layer of the auxiliary electrode, and the first capping layer does not contact the exposed surface of the bottom surface of the second conductive layer.
10. 10 . The display device of claim 9 , wherein the capping layer comprises at least any one of titanium (Ti), molybdenum (Mo), and a conductive oxide.
11. 11 . The display device of claim 10 , wherein the second conductive layer and the third conductive layer comprise at least any one of titanium (Ti), molybdenum (Mo) and a conductive oxide, the first conductive layer comprises at least any one of aluminum (Al) and copper (Cu), and a thickness of the second conductive layer and a thickness of the third conductive layer are smaller than a thickness of the first conductive layer.
12. 12 . The display device of claim 8 , wherein a bottom surface of the second conductive layer of the auxiliary electrode comprises a surface exposed from the first conductive layer of the auxiliary electrode, and the first capping layer contacts a portion of the exposed surface of the bottom surface of the second conductive layer of the auxiliary electrode.
13. 13 . A display device comprising: a thin-film transistor disposed on a substrate; an interlayer insulating layer disposed on the thin-film transistor, a source/drain electrode disposed on the interlayer insulating layer and electrically connected to the thin-film transistor through a contact hole penetrating the interlayer insulating layer, a via insulating layer disposed on the source/drain electrode; a pixel electrode and an auxiliary electrode that are formed as a same layer disposed on the via insulating layer, each of the pixel electrode and the auxiliary electrode comprising a first conductive layer and a second conductive layer disposed on an upper surface of the first conductive layer; a pixel defining layer disposed on the via insulating layer and the pixel electrode, the pixel defining layer having a first opening exposing the auxiliary electrode; a capping layer covering at least a portion of the auxiliary electrode; and a light emitting material layer and a common electrode layer sequentially stacked on the pixel defining layer and the capping layer, wherein the pixel electrode is electrically connected to the source/drain electrode through a contact hole penetrating the via insulating layer, the auxiliary electrode has an undercut shape in which side surfaces of the first conductive layer of the auxiliary electrode are disposed inside side surfaces of the second conductive layer of the auxiliary electrode, the capping layer comprises: a first capping layer covering the side surfaces of the first conductive layer of the auxiliary electrode, and a second capping layer separated from the first capping layer and disposed on an upper surface of the second conductive layer of the auxiliary electrode, and the capping layer comprises a conductive material.
14. 14 . The display device of claim 13 , wherein the light emitting material layer comprises: a first portion disposed on the first capping layer, and a second portion separated from the first portion of the light emitting material layer and disposed on the second capping layer.
15. 15 . The display device of claim 14 , wherein the common electrode layer comprises: a first portion disposed on the first portion of the light emitting material layer and directly contacting the first capping layer; and a second portion separated from the first portion of the common electrode layer and disposed on the second portion of the light emitting material layer.
16. 16 . The display device of claim 13 , wherein the auxiliary electrode further comprises a third conductive layer disposed between the first conductive layer of the auxiliary electrode and the interlayer insulating layer, and the side surfaces of the first conductive layer of the auxiliary electrode are disposed inside side surfaces of the third conductive layer of the auxiliary electrode.
17. 17 . The display device of claim 16 , wherein a thickness of the first capping layer covering the side surfaces of the first conductive layer decreases as the first capping layer is closer to the second conductive layer.

Description

CROSS REFERENCE TO RELATED APPLICATION(S) This application claims priority from to and benefits of Korean Patent Application No. 10-2022-0122939 under 35 U.S.C. § 119, filed on Sep. 28, 2022, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. BACKGROUND 1. Technical Field Embodiments relate to a display device and a method of manufacturing the display device. 2. Description of the Related Art Display devices have been more important with the development of multimedia. Accordingly, various types of display devices such as organic light emitting displays and liquid crystal displays have been used in various fields. A display device includes a display panel such as an organic light emitting display panel or a liquid crystal display panel as a device for displaying an image of the display device. Among them, a light emitting display panel may include light emitting elements such as light emitting diodes (LEDs). For example, the LEDs may be organic light emitting diodes (OLEDs) formed of an organic material as a fluorescent material or may be inorganic LEDs formed of an inorganic material as a fluorescent material. The display device includes a pixel electrode and a common electrode. The pixel electrode is individually driven for each pixel by a thin-film transistor. The same voltage is applied to the common electrode regardless of the pixels. As a display screen becomes larger, the size of the common electrode also increases. For example, a voltage drop phenomenon may occur due to the resistance of the common electrode itself, thereby deteriorating display quality. SUMMARY Embodiments provide a display device which reduces a voltage drop phenomenon of a common electrode. Embodiments also provide a method of manufacturing a display device which reduces a voltage drop phenomenon of a common electrode. However, embodiments of the disclosure are not limited to those set forth herein. The above and other embodiments of the disclosure will become more apparent to one of ordinary skill in the art to which the disclosure pertains by referencing the detailed description of the disclosure given below. In an embodiment, display device may include a thin-film transistor disposed on a substrate, an interlayer insulating layer disposed on the thin-film transistor, a source/drain electrode and an auxiliary electrode that are formed as a same layer disposed on the interlayer insulating layer, each of the source/drain electrode and the auxiliary electrode including a first conductive layer and a second conductive layer disposed on an upper surface of the first conductive layer, a via insulating layer disposed on the interlayer insulating layer and the source/drain electrode and having a first opening exposing the auxiliary electrode, a capping layer covering at least a portion of the auxiliary electrode and a light emitting material layer and a common electrode layer sequentially stacked on an upper surface of the via insulating layer and an upper surface of the capping layer, and the source/drain electrode may be electrically connected to the thin-film transistor through a contact hole penetrating the interlayer insulating layer, the auxiliary electrode may have an undercut shape in which side surfaces of the first conductive layer of the auxiliary electrode are disposed inside side surfaces of the second conductive layer of the auxiliary electrode, the capping layer may include a first capping layer covering the side surfaces of the first conductive layer of the auxiliary electrode and a second capping layer separated from the first capping layer and disposed on an upper surface of the second conductive layer of the auxiliary electrode, and the capping layer may include a conductive material. The display device may further include: a pixel electrode layer disposed between the via insulating layer and each of the capping layer and the light emitting material layer, wherein the pixel electrode layer may include: a pixel electrode electrically connected to the source/drain electrode through a contact hole penetrating the via insulating layer, a first dummy pixel electrode separated from the pixel electrode and disposed on the first capping layer, and a second dummy pixel electrode separated from the first dummy pixel electrode and disposed on the second capping layer. The light emitting material layer may include: a first portion disposed on the first dummy pixel electrode; and a second portion separated from the first portion of the light emitting material layer and disposed on the second dummy pixel electrode. The common electrode layer may include: a first portion disposed on the first portion of the light emitting material layer and directly contacting the first capping layer, and a second portion separated from the first portion of the common electrode layer and disposed on the second portion of the light emitting material layer. The display device may further incl