CN117082919A

CN117082919A - Display device

Info

Publication number: CN117082919A
Application number: CN202310541721.2A
Authority: CN
Inventors: 李东敏; 申铉亿; 朴俊龙; 成炫阿; 郑参台
Original assignee: Samsung Display Co Ltd
Current assignee: Samsung Display Co Ltd
Priority date: 2022-05-16
Filing date: 2023-05-15
Publication date: 2023-11-17

Abstract

A display device includes: a substrate including a display region and a peripheral region outside the display region; a display element arranged in the display area; a transistor including a semiconductor layer and a gate electrode; and a connection electrode electrically connected to the transistor and having a multilayer structure. The connection electrode includes: a main metal layer including a first metal element; and a protective layer disposed on the main metal layer and including a first metal element and a second metal element different from the first metal element.

Description

Display device

The present application claims priority and ownership rights obtained from korean patent application No. 10-2022-0059848, filed on day 5 and 16 of 2022, and No. 10-2022-0085274, filed on day 7 and 11 of 2022, the contents of which are incorporated herein by reference in their entireties.

Technical Field

One or more embodiments relate to a display device.

Background

The display device includes a display element and a transistor electrically connected to the display element. The connection electrode is electrically connected to the semiconductor layer of the transistor, and is configured to transmit an electrical signal to the transistor. However, the connection electrode may be damaged during a subsequent process after the connection electrode is formed.

Disclosure of Invention

One or more embodiments include a display device including a high-quality connection electrode that is not damaged in a subsequent process after its formation and electrical characteristics are not degraded. However, such technical problems are examples, and the present disclosure is not limited thereto.

Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the presented embodiments of the disclosure.

According to one or more embodiments, a display device includes: a substrate including a display region and a peripheral region outside the display region; a display element arranged in the display area; a transistor including a semiconductor layer and a gate electrode; and a connection electrode electrically connected to the transistor and having a multilayer structure, wherein the connection electrode includes: a main metal layer including a first metal element; and a protective layer disposed on the main metal layer and including a first metal element and a second metal element different from the first metal element.

The first metal element may include at least one of copper (Cu), aluminum (Al), platinum (Pt), silver (Ag), gold (Au), and nickel (Ni).

The second metal element may include at least one of titanium (Ti), molybdenum (Mo), and tungsten (W).

The protective layer may include an alloy of copper (Cu) and titanium (Ti).

The display device may further include: and a metal oxide layer disposed on the protective layer and including a metal oxide containing a first metal element and a second metal element.

The display device may further include: and the auxiliary layer is arranged below the main metal layer.

The auxiliary layer may include a second metal element.

The auxiliary layer may include an auxiliary layer tip protruding more in a lateral direction than the main metal layer at a boundary between the auxiliary layer and the main metal layer.

The auxiliary layer may further include a first metal element.

The semiconductor layer may be disposed on the substrate, the gate electrode may be disposed on the gate insulating layer, the gate insulating layer is disposed on the semiconductor layer, and the connection electrode may be electrically connected to the semiconductor layer.

According to one or more embodiments, a display device includes: a substrate including a display region and a peripheral region outside the display region; a display element arranged in the display area; a transistor including a semiconductor layer and a gate electrode; and a connection electrode electrically connected to the transistor and having a multilayer structure, wherein the connection electrode includes: a main metal layer including a first metal element; a first protective layer disposed over the main metal layer and including a first metal element and a second metal element different from the first metal element; and a second protective layer disposed between the main metal layer and the first protective layer and including a second metal element.

The first protective layer may include an alloy of copper (Cu) and titanium (Ti).

The display device may further include: and an oxidized metal layer disposed on the first protective layer and including a metal oxide containing a first metal element and a second metal element.

The auxiliary layer may include a second metal element.

The auxiliary layer may further include a first metal element.

These and/or other aspects will become apparent and more readily appreciated from the following detailed description of the embodiments, the accompanying drawings, and the claims.

Drawings

The foregoing and other aspects, features, and advantages of certain embodiments of the disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic plan view of a display device according to an embodiment;

fig. 2 is an equivalent circuit diagram of a pixel of a display device according to an embodiment;

FIG. 3 is a schematic cross-sectional view of the display device taken along line I-I' of FIG. 1;

fig. 4 to 6 are schematic cross-sectional views illustrating a process of manufacturing a portion of the display device of fig. 3;

fig. 7 is a schematic enlarged cross-sectional view of region II of the display device of fig. 3;

fig. 8 is a schematic enlarged cross-sectional view of region III of the display device of fig. 7;

fig. 9 is a sectional view for explaining a first connection electrode of a display device according to a comparative example;

fig. 10 is a schematic cross-sectional view of a portion of a display device according to an embodiment;

FIG. 11 is a schematic cross-sectional view of a portion of a display device according to another embodiment;

fig. 12 is a schematic enlarged sectional view of a region IV of the display device of fig. 11;

fig. 13 is a schematic enlarged cross-sectional view of a region V of the display device of fig. 12;

fig. 14 to 16 are schematic cross-sectional views illustrating a process of manufacturing a portion of the display device of fig. 11; and is also provided with

Fig. 17 is a view for explaining a portion of the second protective layer forming layer that contacts the etchant when patterning is performed.

Detailed Description

Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as limited to the descriptions set forth herein. Accordingly, the embodiments are described below only by referring to the drawings to explain aspects of the present description. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Throughout this disclosure, the expression "at least one of a, b and c" indicates all of a only, b only, c only, both a and b, both a and c, both b and c, a, b and c, or variants thereof.

Since the disclosure is susceptible of various modifications and numerous embodiments, certain embodiments will be shown in the drawings and described in the written description. The effects and features of the present disclosure and methods of achieving them will be elucidated with reference to the embodiments described in detail below with reference to the drawings. However, the present disclosure is not limited to the following embodiments, and may be embodied in various forms.

Hereinafter, embodiments will be described with reference to the drawings, wherein like reference numerals refer to like elements throughout and repetitive description thereof will be omitted.

As used herein, when various elements such as layers, regions, and panels are disposed "on" another element, it may be meant not only that these elements may be disposed "directly" on "the other element, but also that another element may be disposed therebetween. In addition, the dimensions of the elements in the figures may be exaggerated or reduced for convenience of explanation. As an example, for convenience of description, the size and thickness of each element shown in the drawings are arbitrarily represented, and thus, the present disclosure is not necessarily limited thereto.

The x-axis, y-axis, and z-axis are not limited to three axes in a rectangular coordinate system, and can be interpreted in a broader sense. For example, the x-axis, y-axis, and z-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other.

Although terms such as "first" and "second" may be used to describe various components, such components are not necessarily limited to the above terms. The above terms are used to distinguish one element from another element.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It will be understood that the terms "comprises" and/or "comprising," and variations thereof, as used herein, specify the presence of stated features or components, but do not preclude the addition of one or more other features or components.

In view of the measurements in question and the errors associated with the particular amount of measurements (i.e., limitations of the measurement system), the use of "about" or "approximately" herein includes the stated values and refers to within the acceptable range of deviation of the particular value as determined by one of ordinary skill in the art. For example, "about" may mean within one or more standard deviations, or within ±30%, ±20%, ±10% or ±5% of the stated value.

Fig. 1 is a schematic plan view of a display device 1 according to an embodiment. Here, the "plan view" is a view in the thickness direction (i.e., z direction) of the display device 1 or the substrate 100 (see fig. 3). As shown in fig. 1, the display device 1 may include a display area DA in which a plurality of pixels P are arranged and a peripheral area PA outside the display area DA. Specifically, the peripheral area PA may surround the entire display area DA.

Each pixel P of the display device 1 is a region that can be configured to emit light of a preset color. The display device 1 may be configured to display an image by using light from the pixels P. As an example, each pixel P may be configured to emit red, green, or blue light.

As shown in fig. 1, the display area DA may have a polygonal shape including a quadrangular shape. As an example, the display area DA may have a rectangular shape in which a horizontal length thereof is greater than a vertical length, a rectangular shape in which a horizontal length thereof is less than a vertical length, or a square shape. Alternatively, the display area DA may have various shapes such as an elliptical shape or a circular shape.

The peripheral area PA may be a non-display area in which no pixels are arranged. A driver or the like configured to supply an electric signal or power to the pixels P may be disposed in the peripheral area PA. A plurality of pads (not shown) may be arranged in the peripheral area PA, wherein a pad is an area to which an electronic component or a printed circuit board may be electrically connected. The pads may be separated from each other in the peripheral area PA and electrically connected to the printed circuit board or the integrated circuit element.

Fig. 2 is an equivalent circuit diagram of the pixel P of the display device 1 according to the embodiment. As shown in fig. 2, the pixel P may include a pixel circuit PC and an organic light emitting diode OLED electrically connected to the pixel circuit PC.

The pixel circuit PC may include a first transistor T1, a second transistor T2, and a storage capacitor Cst. The second transistor T2 is a switching transistor, may be connected to the scan line SL and the data line DL, and is configured to transmit a data voltage to the first transistor T1 according to a switching voltage, the data voltage being input from the data line DL, and the switching voltage being input from the scan line SL. The storage capacitor Cst may be connected to the second transistor T2 and the driving voltage line PL, and is configured to store a voltage corresponding to a difference between a voltage transferred from the second transistor T2 and the first power voltage ELVDD supplied to the driving voltage line PL.

The first transistor T1 is a driving transistor, may be connected to a driving voltage line PL and a storage capacitor Cst, and is configured to control a driving current according to a voltage stored in the storage capacitor Cst, the driving current flowing from the driving voltage line PL to the organic light emitting diode OLED. The organic light emitting diode OLED may emit light having a preset brightness corresponding to a driving current. The counter electrode 530 (see fig. 3) of the organic light emitting diode OLED may receive the second power voltage ELVSS.

Although the pixel circuit PC is described with reference to fig. 2 as including two transistors and one storage capacitor, the embodiment is not limited thereto. In another embodiment, the number of transistors and the number of storage capacitors may be variously changed according to the design of the pixel circuit PC.

Fig. 3 is a schematic cross-sectional view of the display device 1 according to the embodiment. Specifically, fig. 3 is a schematic cross-sectional view of the display device 1 taken along the line I-I' of fig. 1.

As shown in fig. 3, the display device 1 according to the embodiment includes a substrate 100. The substrate 100 may include various flexible or bendable materials. As an example, the substrate 100 may include glass, metal, or polymer resin. In addition, the substrate 100 may include a polymer resin such as polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, or cellulose acetate propionate. The substrate 100 may have a multilayer structure including two layers each including a polymer resin and a barrier layer including an inorganic material (e.g., silicon oxide, silicon nitride, and silicon oxynitride) between the two layers. However, various modifications may be made.

A display element and a transistor TFT electrically connected to the display element may be located over the substrate 100. An organic light emitting diode OLED as a display element is shown above the substrate 100 in fig. 3. When the organic light emitting diode OLED is electrically connected to the transistor TFT, it is understood that the pixel electrode 510 is electrically connected to the transistor TFT.

The transistor TFT may include a semiconductor layer 221 and a gate electrode 222, wherein the semiconductor layer 221 includes amorphous silicon, polycrystalline silicon, an organic semiconductor material, or an oxide semiconductor material, and the gate electrode 222 overlaps with a channel region of the semiconductor layer 221 in a plan view. The gate electrode 222 may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), or titanium (Ti), or the like. As an example, the gate electrode 222 may have a multi-layer structure or a single-layer structure including a conductive material. In order to ensure insulation between the semiconductor layer 221 and the gate electrode 222, a gate insulating layer 223 may be disposed between the semiconductor layer 221 and the gate electrode 222, wherein the gate insulating layer 223 includes an inorganic material such as silicon oxide, silicon nitride, and/or silicon oxynitride. The insulating layer including an inorganic material may be formed by chemical vapor deposition ("CVD") or atomic layer deposition ("ALD"). The same applies to the following embodiments and modifications thereof.

The second insulating layer IL2 may be disposed on the gate electrode 222, wherein the second insulating layer IL2 includes an inorganic material such as silicon oxide, silicon nitride, and/or silicon oxynitride. The first connection electrode 430 and the second connection electrode 440 may be disposed on the second insulating layer IL 2. The first connection electrode 430 and the second connection electrode 440 may be electrically connected to the semiconductor layer 221 of the transistor TFT. Specifically, the first connection electrode 430 may be connected to a portion (e.g., a source region) of the semiconductor layer 221 through a contact hole formed in the second insulating layer IL 2. The second connection electrode 440 may be connected to another portion (e.g., a drain region) of the semiconductor layer 221 through another contact hole formed in the second insulating layer IL 2. As an example, the first connection electrode 430 may be a source electrode, and the second connection electrode 440 may be a drain electrode. Alternatively, the first connection electrode 430 may be a drain electrode and the second connection electrode 440 may be a source electrode depending on the polarity of the transistor TFT.

However, the embodiment is not limited thereto. In another embodiment, the display device 1 may include only one of the first connection electrode 430 and the second connection electrode 440. The first connection electrode 430 and the second connection electrode 440 may each have a multi-layered structure including a plurality of sub-layers. Specifically, the first connection electrode 430 may include a main metal layer 433, a first protection layer 437, an oxidized metal layer 438, and an auxiliary layer 431, which are described below.

The storage capacitor Cst may include a first electrode 310 and a second electrode 420. The first electrode 310 of the storage capacitor Cst may be formed during the same process as the formation of the gate electrode 222, and may include the same material as the gate electrode 222. An insulating layer 312 including the same material as the gate insulating layer 223 may be disposed under the first electrode 310. Since the insulating layer 312 under the first electrode 310 is formed during the same mask process as the mask process for forming the first electrode 310, the planar shape of the insulating layer 312 may be substantially the same as the planar shape of the first electrode 310. The second electrode 420 may be formed together during a patterning process for forming the first connection electrode 430 and the second connection electrode 440. Accordingly, the second electrode 420 may have a multi-layered structure as the first and second connection electrodes 430 and 440. The multilayered structure is described in detail below.

The transistor TFT may include a lower metal layer 210 disposed under a semiconductor layer 221. The lower metal layer 210 may be electrically connected to one of the first connection electrode 430 and the second connection electrode 440. In an embodiment, the lower metal layer 210 is shown in fig. 3 to be electrically connected to the first connection electrode 430. The lower metal layer 210 may be a lower first connection electrode.

The lower metal layer 210 may include at least one of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), and copper (Cu). The lower metal layer 210 may improve characteristics of the transistor TFT.

The first insulating layer IL1 may be disposed on the lower metal layer 210. Specifically, the first insulating layer IL1 may be formed on the entire surface of the substrate 100 to cover the lower metal layer 210. The first insulating layer IL1 may include, for example, an inorganic material such as silicon oxide, silicon nitride, and/or silicon oxynitride. The first insulating layer IL1 may increase the flatness of the upper surface of the substrate 100, or prevent or reduce impurities from the substrate 100 from penetrating into the semiconductor layer 221 of the transistor TFT.

A second insulating layer IL2 may be disposed on the gate electrode 222 and the first electrode 310. Specifically, the second insulating layer IL2 may be formed on the entire surface of the substrate 100 to cover the gate electrode 222 and the first electrode 310. Accordingly, the first connection electrode 430, the second connection electrode 440, and the second electrode 420 may be disposed on the second insulation layer IL 2. The second insulating layer IL2 may include, for example, an inorganic material such as silicon oxide, silicon nitride, and/or silicon oxynitride. Alternatively, the second insulating layer IL2 may include, for example, propylene, benzocyclobutene ("BCB"), or hexamethyldisiloxane ("HMDSO"). In this case, the upper surface (in the +z direction) of the second insulating layer IL2 may be planarized.

The third insulating layer IL3 may be disposed on the first connection electrode 430, the second connection electrode 440, and the second electrode 420. Specifically, the third insulating layer IL3 may be formed on the entire surface of the substrate 100 to cover the first connection electrode 430, the second connection electrode 440, and the second electrode 420. The third insulating layer IL3 may include, for example, an inorganic material such as silicon oxide, silicon nitride, and/or silicon oxynitride.

The organic insulating layer OL may be disposed on the third insulating layer IL 3. As an example, as shown in fig. 3, in the case where the organic light emitting diode OLED is disposed over the first connection electrode 430, the second connection electrode 440, and the second electrode 420, the organic insulating layer OL may substantially planarize an upper portion of a protective layer covering the first connection electrode 430, the second connection electrode 440, and the second electrode 420. The organic insulating layer OL may include an organic material such as acryl, benzocyclobutene (BCB), or Hexamethyldisiloxane (HMDSO). Although the organic insulating layer OL is shown as a single layer in fig. 3, the organic insulating layer OL may be a plurality of layers. However, various modifications may be made.

The display element may be located on the organic insulating layer OL. For the display element, the organic light emitting diode OLED shown in fig. 3 may be used. The organic light emitting diode OLED may include, for example, a pixel electrode 510, a counter electrode 530, and an intermediate layer 520 between the pixel electrode 510 and the counter electrode 530, wherein the intermediate layer 520 includes an emission layer. The pixel electrode 510 may be electrically connected to the transistor TFT. Specifically, as shown in fig. 3, the pixel electrode 510 may be connected to the first connection electrode 430 or the second connection electrode 440 through a contact hole formed in the organic insulation layer OL. The first connection electrode 430 or the second connection electrode 440 may be electrically connected to the transistor TFT. The pixel electrode 510 includes a light-transmitting conductive layer including, for example, indium tin oxide ("ITO"), oxygen, and a reflective layer Indium oxide (In) ₂ O ₃ ) Or indium zinc oxide ("IZO"), and the reflective layer includes a metal such as aluminum (Al) or silver (Ag). As an example, the pixel electrode 510 may have a three-layer structure of ITO/Ag/ITO.

The intermediate layer 520 of the organic light emitting diode OLED may include a low molecular weight material or a polymer material. In the case where the intermediate layer 520 includes a low molecular weight material, the intermediate layer 520 may have a structure in which a hole injection layer ("HIL"), a hole transport layer ("HTL"), an emission layer ("EML"), an electron transport layer ("ETL"), an electron injection layer ("EIL"), and the like are stacked in a single or composite configuration. Intermediate layer 520 may include, for example, copper phthalocyanine (CuPc), N '-bis (1-naphthyl) -N, N' -diphenyl-benzidine ("NPB"), and tris- (8-hydroxyquinoline) aluminum (Alq) ₃ ) Is a material for a semiconductor device. These layers may be formed by vacuum deposition.

In the case where the intermediate layer 520 includes a polymer material, the intermediate layer 520 may have a structure including an HTL and an EML. In this case, the HTL may include poly (3, 4-ethylenedioxythiophene) ("PEDOT"), and the EML may include a polymer material such as a polystyrene ("PPV") type material and a polyfluorene type material. The intermediate layer 520 may be formed by screen printing, inkjet printing, laser induced thermal imaging ("LITI"), or the like.

The intermediate layer 520 is not necessarily limited thereto, but may have various structures. The intermediate layer 520 may include a layer integrated throughout the plurality of pixel electrodes 510, or include a layer patterned to correspond to each of the plurality of pixel electrodes 510.

The counter electrode 530 is disposed in the display area DA, and may be disposed to cover the display area DA as shown in fig. 3. That is, the counter electrode 530 may be integrally formed throughout the plurality of organic light emitting diodes OLED, and may correspond to the plurality of organic light emitting diodes OLED. The counter electrode 530 may include a material including ITO, in ₂ O ₃ Or IZO, and includes a semi-transmissive layer including a metal such as aluminum (Al) or silver (Ag). As an example, the counter electrode 530 may be a semi-transmissive layer including magnesium (Mg) and silver (Ag).

The pixel defining layer UIL may be disposed on the organic insulating layer OL. The pixel defining layer UIL defines pixels by including an opening corresponding to each pixel (i.e., an opening exposing at least a central portion of the pixel electrode 510). In addition, as shown in fig. 3, the pixel defining layer UIL may prevent arcing or the like from occurring at the edge of the pixel electrode 510 by increasing the distance between the edge of the pixel electrode 510 and the counter electrode 530. The pixel defining layer UIL may comprise an organic material such as polyimide or HMDSO.

Since the organic light emitting diode OLED may be easily damaged by external moisture or oxygen, etc., the encapsulation layer 600 may protect the organic light emitting diode OLED by covering the organic light emitting diode OLED. The encapsulation layer 600 may cover the display area DA and extend to the outside of the display area DA. As shown in fig. 3, the encapsulation layer 600 may include a first inorganic encapsulation layer 610, an organic encapsulation layer 620, and a second inorganic encapsulation layer 630.

The first inorganic encapsulation layer 610 may cover the counter electrode 530 and may include silicon oxide, silicon nitride, and/or silicon oxynitride. Other layers including a capping layer may be disposed between the first inorganic encapsulation layer 610 and the counter electrode 530, as needed. Because the first inorganic encapsulation layer 610 is formed along the structure thereunder, the upper surface of the first inorganic encapsulation layer 610 is not flat, as shown in fig. 3. The organic encapsulation layer 620 may cover the first inorganic encapsulation layer 610, and unlike the first inorganic encapsulation layer 610, an upper surface of the organic encapsulation layer 620 may be approximately flat. Specifically, the upper surface of the portion of the organic encapsulation layer 620 corresponding to the display area DA may be approximately flat. The organic encapsulation layer 620 may include at least one material among polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polysulfonate, polyoxymethylene, polyarylate, and hexamethyldisiloxane. The second inorganic encapsulation layer 630 may cover the organic encapsulation layer 620 and may include silicon oxide, silicon nitride, and/or silicon oxynitride. Since the second inorganic encapsulation layer 630 contacts the first inorganic encapsulation layer 610 at an edge outside the display area DA, the organic encapsulation layer 620 is not exposed to the outside.

Since the encapsulation layer 600 includes the first inorganic encapsulation layer 610, the organic encapsulation layer 620, and the second inorganic encapsulation layer 630, even when a crack occurs inside the encapsulation layer 600, the crack is not connected between the first inorganic encapsulation layer 610 and the organic encapsulation layer 620 or between the organic encapsulation layer 620 and the second inorganic encapsulation layer 630 through the above-described multi-layer structure. With this configuration, it is possible to prevent or reduce the formation of a path through which external moisture or oxygen penetrates the display area DA.

Fig. 4 to 6 are schematic cross-sectional views showing a process of manufacturing a part of the display device 1 of fig. 3. In particular, fig. 4 to 6 are schematic cross-sectional views illustrating a process of manufacturing the first connection electrode 430, the second connection electrode 440, and the second electrode 420 of the display device 1 of fig. 3.

First, as shown in fig. 4, an auxiliary layer forming layer 460 may be formed over the substrate 100, a main metal layer forming layer 470 may be formed on the auxiliary layer forming layer 460, and a preliminary first protective layer forming layer 490P may be formed on the main metal layer forming layer 470. In this specification, an "auxiliary layer forming layer" means a layer in which the shape of the auxiliary layer 431 is not patterned after deposition of the auxiliary layer forming material, a "main metal layer forming layer" means a layer in which the shape of the main metal layer 433 is not patterned after deposition of the main metal forming material, and a "preliminary first protective layer forming layer" means a layer in which a part of the first protective layer forming material is not oxidized by oxygen or the like in the atmosphere after deposition of the first protective layer forming material.

Specifically, the auxiliary layer forming material, the main metal layer forming material, and the first protective layer forming material may be sequentially deposited. As an example, the auxiliary layer forming layer 460 may be formed over the substrate 100 by depositing an auxiliary layer forming material over the entire surface of the substrate 100 using a sputtering method or the like in the chamber. Then, the main metal layer forming layer 470 may be formed on the auxiliary layer forming layer 460 by depositing a main metal layer forming material on the entire surface of the substrate 100 using a sputtering method or the like in the same chamber. Then, a preliminary first protective layer forming layer 490P may be formed on the main metal layer forming layer 470 by depositing a first protective layer forming material on the entire surface of the substrate 100 in the same chamber. However, the embodiment is not limited thereto. In another embodiment, the auxiliary layer forming layer 460, the main metal layer forming layer 470, and the preliminary first protective layer forming layer 490P may be formed in different chambers, respectively.

The main metal layer forming material may include a first metal element, and the auxiliary layer forming material may include a second metal element different from the first metal element. The first protective layer forming material may include a first metal element and a second metal element. The first metal element may include at least one of copper (Cu), aluminum (Al), platinum (Pt), silver (Ag), gold (Au), and nickel (Ni) in view of conductivity and the like. The second metal element may include at least one of titanium (Ti), molybdenum (Mo), and tungsten (W). Hereinafter, for convenience of description, a case where the first metal element is Cu and the second metal element is Ti is mainly described in detail.

As an example, the main metal layer forming material may include Cu, the auxiliary layer forming material may include Ti, and the first protective layer forming material may include Cu and Ti. Accordingly, the main metal layer forming layer 470 may include Cu, the auxiliary layer forming layer 460 may include Ti, and the preliminary first protective layer forming layer 490P may include Cu and Ti.

Subsequently, as shown in fig. 5, the oxidized metal layer forming layer 495 may be formed by oxidizing a portion of the preliminary first protective layer forming layer 490P. The first protective layer forming layer 490 may be disposed under the metal oxide layer forming layer 495. In this specification, the "oxidized metal layer forming layer" is a layer which prepares a portion of the first protective layer forming layer 490P to be oxidized by oxygen in the atmosphere or the like and indicates that the shape of the oxidized metal layer 438 is not patterned, and the "first protective layer forming layer" is a layer which prepares a portion of the first protective layer forming layer 490P which is not oxidized by oxygen in the atmosphere or the like and indicates that the shape of the first protective layer 437 is not patterned. As an example, in the case where the auxiliary layer forming layer 460, the main metal layer forming layer 470, and the preliminary first protective layer forming layer 490P are formed on the entire surface of the substrate 100 in the same chamber by using a sputtering method or the like, the preliminary first protective layer forming layer 490P located at the uppermost portion of these layers may be exposed to the outside. Accordingly, ti and Cu included in the preliminary first protective layer formation layer 490P can be easily oxidized by oxygen in the atmosphere. Alternatively, ti and Cu included in the preliminary first protective layer forming layer 490P may be easily oxidized by pure water during a cleaning process using pure water before the patterning process. Accordingly, the metal oxide layer forming layer 495 may be formed on the first protective layer 490, wherein the metal oxide layer forming layer 495 is formed by oxidizing a portion of the preliminary first protective layer 490P.

Subsequently, as shown in fig. 6, the first connection electrode 430 including the auxiliary layer 431, the main metal layer 433, the first protection layer 437, and the oxidized metal layer 438 may be formed by patterning the auxiliary layer forming layer 460, the main metal layer forming layer 470, the first protection layer 490, and the oxidized metal layer forming layer 495.

The auxiliary layer forming layer 460, the main metal layer forming layer 470, the first protective layer forming layer 490, and the metal oxide layer forming layer 495 may be patterned such that the second connection electrode 440 and the second electrode 420 are formed together during the patterning process. Accordingly, the second connection electrode 440 and the second electrode 420 may have a multi-layered structure as the first connection electrode 430. Accordingly, the sub-layers 421, 423, 427, and 428 of the second electrode 420 and the sub-layer of the second connection electrode 440 may include the same materials as those of the auxiliary layer 431, the main metal layer 433, the first protection layer 437, and the oxidized metal layer 438, respectively, which are the sub-layers of the first connection electrode 430.

The rate at which the above-described formation layers are etched by the etchant used during the patterning process may vary for each formation layer. In general, the rate at which a metal layer including one metal element is etched may be different from the rate at which a metal layer including another metal element is etched. Specifically, the metal layer including Ti may be etched at a slower rate than the metal layer including Cu. As an example, the main metal layer forming layer 470 may include Cu, the auxiliary layer forming layer 460 may include Ti, and the first protective layer forming layer 490 may include Cu and Ti. In this case, the first protective layer formation layer 490 may be etched faster than the auxiliary layer formation layer 460. The main metal layer forming layer 470 may be etched faster than the first protective layer forming layer 490.

Accordingly, the shapes of the sub-layers 431, 433, 437 and 438 included in the first connection electrode 430 may be different from each other. Since the main metal layer forming layer 470 is etched faster than the auxiliary layer forming layer 460 is etched, the auxiliary layer 431 may be formed to protrude more than the main metal layer 433 in a lateral direction (e.g., -x direction or +x direction). Here, the lateral direction may be a direction perpendicular to the thickness direction (z direction). The auxiliary layer 431 formed through this manufacturing process may include a second metal element, and the main metal layer 433 may include a first metal element.

In the case where the main metal layer forming layer 470 includes the first metal element and the first protective layer forming layer 490 includes the first metal element, the difference between the speed at which the main metal layer forming layer 470 is etched and the speed at which the first protective layer forming layer 490 is etched may be reduced, compared to the case where the main metal layer forming layer 470 includes the first metal element and the first protective layer forming layer 490 includes the second metal element. That is, in the case where the main metal layer forming layer 470 includes copper (Cu) and the first protective layer forming layer 490 includes copper (Cu) and titanium (Ti), a difference between a speed at which the main metal layer forming layer 470 is etched and a speed at which the first protective layer forming layer 490 is etched can be reduced, as compared with the case where the main metal layer forming layer 470 includes copper (Cu) and the first protective layer forming layer 490 includes titanium (Ti).

The metal layer including one metal element may be etched faster than the metal oxide layer including the same metal element as the metal element of the metal layer. As an example, the metal oxide layer including Ti and Cu may be etched at a slower rate than the metal layer including Ti and Cu. That is, the first protective layer forming layer 490 may be etched faster than the metal oxide layer forming layer 495 is etched.

The rate at which the metal oxide layer is etched may be different depending on the metal element included in the metal oxide layer. As an example, copper oxide (CuO _x ) Can be compared with titanium oxide (T)iO _x ) The etching is fast. In the case where the metal oxide layer forming layer 495 includes Ti and Cu, the metal oxide layer forming layer 495 may include titanium oxide (TiO _x ) And copper oxide (CuO) _x ). Accordingly, in the case where the oxidized metal layer forming layer 495 includes the first metal element and the second metal element, the oxidized metal layer forming layer 495 may be etched faster than in the case where the oxidized metal layer forming layer 495 includes only the second metal element. That is, in the case where the metal oxide layer forming layer 495 includes Cu and Ti, the metal oxide layer forming layer 495 may be etched faster than in the case where the metal oxide layer forming layer 495 includes only Ti.

As described above, in the case where the first protective layer 490 includes the first metal element and the second metal element, the first protective layer 490 may be etched faster than in the case where the first protective layer 490 includes only the second metal element. In the case where the oxidized metal layer forming layer 495 includes the first metal element and the second metal element, the oxidized metal layer forming layer 495 may be etched faster than in the case where the oxidized metal layer forming layer 495 includes only the second metal element. Accordingly, in the case where the main metal layer forming layer 470 includes the first metal element and the first protective layer forming layer 490 and the oxidized metal layer forming layer 495 include the first metal element and the second metal element, a difference between a speed at which the main metal layer forming layer 470 is etched and a speed at which the first protective layer forming layer 490 and the oxidized metal layer forming layer 495 are etched can be reduced. Accordingly, the first protective layer 437 and the oxidized metal layer 438 may not protrude more than the main metal layer 433 in the lateral direction (e.g., -x direction or +x direction). The first protective layer 437 and the oxidized metal layer 438 formed by the manufacturing process may include a first metal element and a second metal element.

The second electrode 420 and the second connection electrode 440 may be formed together during a patterning process for forming the first connection electrode 430. Accordingly, the sub-layers 421, 423, 427, and 428 of the second electrode 420 and the sub-layer of the second connection electrode 440 may have the same or similar shape as the auxiliary layer 431, the main metal layer 433, the first protection layer 437, and the oxidized metal layer 438, respectively, which are sub-layers of the first connection electrode 430.

Fig. 7 is a schematic enlarged sectional view of the first connection electrode 430 of the display device 1 according to the embodiment, showing a region II of the display device 1 of fig. 3, and fig. 8 is a schematic enlarged sectional view of a region III of the display device 1 of fig. 7.

As shown in fig. 7, the first connection electrode 430 may have a multi-layered structure including a plurality of sub-layers. As an example, the first connection electrode 430 may include a main metal layer 433, a first protection layer 437, a metal oxide layer 438, and an auxiliary layer 431.

The main metal layer 433 is a sub-layer occupying most of the first connection electrode 430. When the main metal layer 433 occupies most of the first connection electrode 430, this may mean that the thickness t3 of the main metal layer 433 in the thickness direction (z direction) is 50% or more of the entire thickness Tce of the first connection electrode 430. Specifically, the thickness t3 of the main metal layer 433 may be 60% or more or 70% or more of the entire thickness Tce of the first connection electrode 430. The thickness t3 of the main metal layer 433 may be 10 times or more the thickness of the other layers (for example, the thickness t1 of the auxiliary layer 431 or the thickness t7 of the first protective layer 437). The thickness t3 of the main metal layer 433 may be aboutTo about->As an example, the thickness t3 of the main metal layer 433 may be about

The main metal layer 433 may include a first metal element. The first metal element may include at least one of copper (Cu), aluminum (Al), platinum (Pt), silver (Ag), gold (Au), and nickel (Ni) in view of conductivity and the like. That is, the main metal layer 433 may include a single-layer or multi-layer structure including the first metal element. Specifically, the first metal element may include Cu. As an example, the main metal layer 433 may include a single Cu layer. However, the embodiment is not limited thereto. In another embodiment, the main metal layer 433 may further include at least one of magnesium (Mg), indium (In), boron (B), and niobium (Nb).

The first protective layer 437 may be disposed on the main metal layer 433. The first protective layer 437 may be configured to prevent damage to the main metal layer 433 by an etching process included in the process of manufacturing the display device 1. As an example, in order to prevent the main metal layer 433 from being damaged by an etchant used during a process of etching the pixel electrode 510 of the organic light emitting diode OLED of the display device 1, a first protective layer 437 may be disposed on the main metal layer 433.

The first protective layer 437 may include a conductive material that may protect the main metal layer 433. As an example, the first protective layer 437 may include a second metal element different from the first metal element. Specifically, the second metal element may include at least one of titanium (Ti), molybdenum (Mo), and tungsten (W). The first protective layer 437 may further include a first metal element. As an example, in the case where the main metal layer 433 includes Cu, the first protective layer 437 may further include Cu. That is, the first protective layer 437 may include an alloy of the first metal element and the second metal element. As an example, the first protective layer 437 may include an alloy of Ti and Cu. In this case, the content of the first metal element in the first protective layer 437 may be about 20 atomic percent (at%) to about 80at%, and the content of the second metal element in the first protective layer 437 may be about 20at% to about 80at%.

The thickness t7 of the first protective layer 437 may be smaller than the thickness t3 of the main metal layer 433. As an example, the thickness t7 of the first protective layer 437 may be aboutTo about->Specifically, the thickness t7 of the first protective layer 437 may be aboutThe main metal layer 433 and the first protective layer 437 may be sequentially formed, and thus, the main metal layer 433The upper surface may directly contact the lower surface of the first protective layer 437. The first protective layer 437 may further include Ti as compared to the main metal layer 433. In the case where the first protective layer 437 further includes a material not included in the main metal layer 433, the boundary between the main metal layer 433 and the first protective layer 437 can be identified by a material difference in the cross section of the first connection electrode 430. However, the embodiment is not limited thereto. Since the first protective layer 437 further includes a metal element (e.g., a second metal element) not included in the main metal layer 433, a boundary between the main metal layer 433 and the first protective layer 437 can be identified by using the content of the second metal element. As an example, when the composition is analyzed in a direction (+z direction) from the main metal layer 433 to the first protective layer 437, a portion where the content of the second metal element is increased may correspond to the first protective layer 437.

The oxidized metal layer 438 may be disposed on the first protective layer 437. The oxidized metal layer 438 may be a metal oxide including a first metal element and a second metal element. As an example, in the case where the main metal layer 433 includes Cu and the first protective layer 437 includes Cu and Ti, the oxidized metal layer 438 may include CuO _x And TiO _x 。

The thickness t8 of the oxidized metal layer 438 may be less thanSince the first protective layer 437 and the oxidized metal layer 438 include the same metal element (e.g., the first metal element and the second metal element), the boundary between the first protective layer 437 and the oxidized metal layer 438 can be identified by using the content of oxygen. As an example, when the composition is analyzed in a direction (+z direction) from the first protective layer 437 to the metal oxide layer 438, a portion where the oxygen content is increased may correspond to the metal oxide layer 438.

The auxiliary layer 431 may be disposed on a lower surface of the main metal layer 433 and configured to improve an adhesive force between the first connection electrode 430 and a layer (e.g., the second insulating layer IL 2) located under the first connection electrode 430.

The auxiliary layer 431 may include a first metal element different from the first metal elementTwo metal elements. As an example, the auxiliary layer 431 may be a metal auxiliary layer including a metal such as Ti selected in consideration of conductivity and adhesion. The thickness t1 of the auxiliary layer 431 may be smaller than the thickness t3 of the main metal layer 433. As an example, the thickness t1 of the auxiliary layer 431 may be from about To about->Within a range of (2). Specifically, the thickness t1 of the auxiliary layer 431 may be about +.>/>

The auxiliary layer 431 and the main metal layer 433 may be sequentially formed, and thus, an upper surface of the auxiliary layer 431 may directly contact a lower surface of the main metal layer 433. The auxiliary layer 431 may include Ti, and the main metal layer 433 may include Cu. In the case where the auxiliary layer 431 and the main metal layer 433 include materials different from each other as described above, the boundary between the auxiliary layer 431 and the main metal layer 433 may be identified by the material difference in the cross section of the first connection electrode 430.

As shown in fig. 7, the third insulating layer IL3 may define therein a first hole IL3-H overlapping the first connection electrode 430 in a plan view. The organic insulating layer OL may be disposed on the third insulating layer IL3, and may define therein a second hole OL-H overlapping the first hole IL3-H in a plan view. The width of the second hole OL-H of the organic insulating layer OL in the lateral direction may be different from the width of the first hole IL3-H. As an example, as shown in fig. 7, the width of the second hole OL-H may be smaller than the width of the first hole IL3-H. The pixel electrode 510 may be connected to the first connection electrode 430 through the first and second holes IL3-H and OL-H. Although the pixel electrode 510 is shown connected to the first connection electrode 430 in fig. 3 and 7, the embodiment is not limited thereto. In another embodiment, the pixel electrode 510 may be connected to the second connection electrode 440.

As shown in fig. 7, the side surface of the main metal layer 433 may include a tapered slope such that a sectional area cut through a horizontal plane defined by the x-direction and the y-direction decreases in the +z-direction. Accordingly, the first connection electrode 430 having a multi-layered structure may have a substantially tapered slope. In the case where the first connection electrode 430 has a tapered slope, the step coverage of the third insulating layer IL3 covering the edge of the first connection electrode 430 on the first connection electrode 430 may be improved.

Specifically, the side surface of the main metal layer 433 may have a first inclination angle θ1 with respect to the above-mentioned horizontal plane. The first inclination angle θ1 may be about 30 ° to about 80 °. The first protective layer 437 and the oxidized metal layer 438 may not protrude more than the main metal layer 433 in the lateral direction (e.g., -x direction or +x direction). In this case, the side surface of the first protective layer 437 may have a second inclination angle θ2 equal to or close to the first inclination angle θ1 with respect to the above-described horizontal plane, and the side surface of the metal oxide layer 438 may have an inclination angle equal to or close to the first inclination angle θ1.

As shown in fig. 9, which is a sectional view for explaining a first connection electrode of a display device according to a comparative example, in the case where the first protective layer 437_1 and the oxidized metal layer 438_1 protrude more in the lateral direction (e.g., -x direction or +x direction) than the main metal layer 433, the first protective layer 437_1 and the oxidized metal layer 438_1 may have tips protruding more in the lateral direction (e.g., -x direction or +x direction) than the main metal layer 433 at the boundary between the first protective layer 437_1 and the main metal layer 433. In this case, the inclination angle θ3 of the side surface of the first protective layer 437_1 with respect to the above-described horizontal plane may exceed 90 °. Accordingly, the step coverage of the third insulating layer IL3 covering the edge of the first connection electrode 430_1 on the first connection electrode 430_1 may be reduced as compared to the step coverage in the embodiment of fig. 7.

However, in the display device 1 according to the embodiment, the first protective layer 437 may include a first metal element and a second metal element, and the oxidized metal layer 438 may include the first metal element and the second metal element. As described above with reference to fig. 4 to 6, in this case, the first protective layer 437 and the oxidized metal layer 438 do not protrude more than the main metal layer 433 in the lateral direction (e.g., -x direction or +x direction). Accordingly, the step coverage of the third insulating layer IL3 is not reduced. Accordingly, since no crack occurs in the third insulating layer IL3, the electrical characteristics and the like of the display device 1 are not deteriorated.

In the display device 1 according to the embodiment, the auxiliary layer 431 may include a first metal element. In this case, as described above with reference to fig. 4 to 6, the auxiliary layer 431 may be formed to protrude more than the main metal layer 433 in a lateral direction (e.g., -x direction or +x direction). That is, the auxiliary layer 431 may include an auxiliary layer tip 431T protruding more in a lateral direction (e.g., -x direction or +x direction) than a layer disposed in the vicinity. As an example, as shown in fig. 7, the auxiliary layer 431 may protrude more than any one of the main metal layer 433, the first protective layer 437, and the oxidized metal layer 438 in the lateral direction (e.g., -x direction or +x direction), and form an auxiliary layer tip 431T.

As described above, the auxiliary layer 431 may be disposed on the lower surface of the main metal layer 433 and configured to improve adhesion between the first connection electrode 430 and a layer (e.g., the second insulating layer IL 2) located under the first connection electrode 430. Since the auxiliary layer 431 includes the auxiliary layer tip 431T, a contact area between the auxiliary layer 431 and the second insulating layer IL2 may be increased. Accordingly, the adhesion between the auxiliary layer 431 and the second insulating layer IL2 may be improved. That is, the adhesive force between the first connection electrode 430 and the layer located under the first connection electrode 430 may be improved more.

However, the embodiment is not limited thereto. In another embodiment, the auxiliary layer 431 may include a first metal element and a second metal element. That is, the auxiliary layer forming layer 460 may include a first metal element and a second metal element. As an example, the auxiliary layer 431 may include an alloy of Ti and Cu. In this case, the content of the first metal element in the auxiliary layer 431 may be about 20at% to about 80at%, and the content of the second metal element in the auxiliary layer 431 may be about 20at% to about 80at%.

In the case where the main metal layer forming layer 470 includes the first metal element and the auxiliary layer forming layer 460 includes the first metal element, the difference between the speed at which the main metal layer forming layer 470 is etched and the speed at which the auxiliary layer forming layer 460 is etched may be reduced, compared to the case where the main metal layer forming layer 470 includes the first metal element and the auxiliary layer forming layer 460 includes the second metal element. That is, in the case where the main metal layer forming layer 470 includes copper (Cu) and the auxiliary layer forming layer 460 includes copper (Cu) and titanium (Ti), a difference between a speed at which the main metal layer forming layer 470 is etched and a speed at which the auxiliary layer forming layer 460 is etched can be reduced, as compared with the case where the main metal layer forming layer 470 includes copper (Cu) and the auxiliary layer forming layer 460 includes titanium (Ti). As shown in fig. 10, which is a schematic cross-sectional view of a part of the display device 1 according to an embodiment, in this case, at the boundary between the auxiliary layer 431_1 and the main metal layer 433, the auxiliary layer 431_1 may not include such a tip 431T protruding in the lateral direction (e.g., -x direction or +x direction) than the layer arranged in the vicinity as shown in fig. 7. Accordingly, since the area occupied by the first connection electrode 430_2 is narrow, space utilization may be more efficient than the embodiment of fig. 7.

Fig. 11 is a schematic cross-sectional view of a portion of the display device 2 according to another embodiment, fig. 12 is a schematic enlarged cross-sectional view of a region IV of the display device 2 of fig. 11, and fig. 13 is a schematic enlarged cross-sectional view of a region V of the display device 2 of fig. 12. Since the display device 2 according to the embodiment is similar to the display device 1 described above with reference to fig. 1 to 10, differences from the display device 1 described with reference to fig. 1 to 10 will be mainly described below. In fig. 11 to 13, the same reference numerals as those in fig. 1 to 10 denote the same members, and thus, repetitive description thereof is omitted.

As shown in fig. 11 and 12, the first connection electrode 430_3 of the display device 2 may include a main metal layer 433, a second protection layer 435, a first protection layer 437, a metal oxide layer 438, and an auxiliary layer 431. That is, the first connection electrode 430_3 included in the display device 2 may further include a second protection layer 435 as compared to the first connection electrode 430 included in the display device 1. Since the description of the main metal layer 433, the first protective layer 437, the oxidized metal layer 438, and the auxiliary layer 431 included in the display device 1 is applicable to the main metal layer 433, the first protective layer 437, the oxidized metal layer 438, and the auxiliary layer 431 in the display device 2, repeated descriptions related to these are omitted.

The second protective layer 435 may be disposed between the main metal layer 433 and the first protective layer 437. The second protective layer 435 may be configured to prevent the etchant from traveling toward the main metal layer 433 through cracks, if any, that may occur in the first protective layer 437. The second protective layer 435 may comprise a material different from the material of the main metal layer 433. As an example, the second protective layer 435 may include a second metal element. As described above, the second metal element may include at least one of titanium (Ti), molybdenum (Mo), and tungsten (W). That is, the second protective layer 435 may include a metal layer including a metal element such as Ti, mo, and/or W. The second protective layer 435 may include a single-layer or multi-layer structure including a second metal element. In an embodiment, the second protective layer 435 may have a single layer structure such as a titanium layer, a molybdenum layer, or a tungsten layer. Alternatively, the second protective layer 435 may have a multilayer structure in which these layers are stacked.

As with the second connection electrode 440 and the second electrode 420 included in the display device 1, the second connection electrode 440_1 and the second electrode 420_1 included in the display device 2 may include a multi-layer structure as in the first connection electrode 430_3. Accordingly, the sub-layers 421, 423, 425, 427, and 428 of the second electrode 420_1 and the sub-layer of the second connection electrode 440_1 may include the same materials as those of the auxiliary layer 431, the main metal layer 433, the second protection layer 435, the first protection layer 437, and the oxidized metal layer 438, respectively, which are the sub-layers of the first connection electrode 430_3.

The thickness t5 of the second protective layer 435 may be less than the thickness t3 of the main metal layer 433. As an example, the thickness t5 of the second protective layer 435 may be aboutTo about->Specifically, the thickness t5 of the second protective layer 435 may be aboutIn the case where the display device 2 includes the second protective layer 435, the thickness t7 of the first protective layer 437 included in the display device 2 may be less than +.>That is, the thickness t5 of the second protective layer 435 of the display device 2 may be greater than the thickness t7 of the first protective layer 437 of the display device 2. However, the embodiment is not limited thereto, and the thickness t7 of the first protective layer 437 of the display device 2 may be greater than the thickness t5 of the second protective layer 435 of the display device 2.

As shown in fig. 12, the second protective layer 435 may not protrude more than the main metal layer 433 in the lateral direction (e.g., -x direction or +x direction). In this case, the side surface of the second protective layer 435 may have an inclination angle equal to or similar to the first inclination angle θ1. The side surface of the main metal layer 433 may have a first inclination angle θ1 of about 30 ° to about 80 °, and the side surface of the second protection layer 435, the side surface of the first protection layer 437, and the side surface of the oxidized metal layer 438 may have an inclination angle equal to or close to the first inclination angle θ1. Accordingly, as with the first connection electrode 430 of the display device 1, the first connection electrode 430_3 of the display device 2 may have a substantially tapered slope.

Fig. 14 to 16 are schematic cross-sectional views showing a process of manufacturing a part of the display device 2 of fig. 11. Specifically, fig. 14 to 16 are schematic cross-sectional views showing a process of manufacturing the first connection electrode 430_3, the second connection electrode 440_1, and the second electrode 420_1 of the display device 2 of fig. 11. Since the process of manufacturing the display device 2 is similar to the process of manufacturing the display device 1 described above with reference to fig. 4 to 6, differences from the process of manufacturing the display device 1 described above with reference to fig. 4 to 6 will be mainly described below. In fig. 14 to 16, the same reference numerals as those in fig. 4 to 6 denote the same members, and thus, repetitive description thereof is omitted.

First, as shown in fig. 14, an auxiliary layer forming layer 460 may be formed over the substrate 100, and a main metal layer forming layer 470 may be formed on the auxiliary layer forming layer 460. Then, a second protective layer forming layer 480 may be formed on the main metal layer forming layer 470, and a preliminary first protective layer forming layer 490P may be formed on the second protective layer forming layer 480. In this specification, the second protective layer forming layer means a layer in which the shape of the second protective layer 435 is not patterned after the second protective layer forming material is deposited.

Specifically, the auxiliary layer forming material, the main metal layer forming material, the second protective layer forming material, and the first protective layer forming material may be sequentially deposited. As an example, the auxiliary layer forming layer 460 may be formed over the substrate 100 by depositing an auxiliary layer forming material over the entire surface of the substrate 100 using a sputtering method or the like in the chamber. Then, the main metal layer forming layer 470 may be formed on the auxiliary layer forming layer 460 by depositing a main metal layer forming material on the entire surface of the substrate 100 using a sputtering method or the like in the same chamber. Then, the second protective layer forming layer 480 may be formed on the main metal layer forming layer 470 by depositing a second protective layer forming material on the entire surface of the substrate 100 in the same chamber. Then, a preliminary first protective layer formation layer 490P may be formed on the second protective layer formation layer 480 by depositing a first protective layer formation material on the entire surface of the substrate 100 in the same chamber. However, the embodiment is not limited thereto. In another embodiment, the auxiliary layer 431, the main metal layer 433, the second protective layer 435, and the first protective layer 437 may be formed in different chambers, respectively.

The second protective layer forming material may include a second metal element different from the first metal element. As described above, the second metal element may include at least one of titanium (Ti), molybdenum (Mo), and tungsten (W). The second protective layer forming material may not include the first metal element. Hereinafter, for convenience of description, a case where the second protective layer forming material includes Ti as the second metal element will be mainly described in detail.

Subsequently, as shown in fig. 15, the oxidized metal layer forming layer 495 may be formed by oxidizing a portion of the preliminary first protective layer forming layer 490P. As described above, since the preliminary first protective layer formation layer 490P is exposed to the outside, ti and Cu included in the preliminary first protective layer formation layer 490P can be easily oxidized by oxygen or the like in the atmosphere. Accordingly, the metal oxide layer forming layer 495 may be formed on the first protective layer 490, wherein the metal oxide layer forming layer 495 is formed by oxidizing a portion of the preliminary first protective layer 490P. Subsequently, as shown in fig. 16, the first connection electrode 430_3 may be formed by patterning the auxiliary layer forming layer 460, the main metal layer forming layer 470, the second protective layer forming layer 480, the first protective layer forming layer 490, and the oxidized metal layer forming layer 495, wherein the first connection electrode 430_3 includes the auxiliary layer 431, the main metal layer 433, the second protective layer 435, the first protective layer 437, and the oxidized metal layer 438.

As described above, the rate at which the metal layer including one metal element is etched may be different from the rate at which the metal layer including the other metal element is etched. Accordingly, since the main metal layer forming layer 470 including Cu may be etched faster than the auxiliary layer forming layer 460 including Ti, the auxiliary layer 431 may be formed to protrude more than the main metal layer 433 in a lateral direction (e.g., -x direction or +x direction).

The second protective layer forming layer 480 includes Ti, but the second protective layer 435 may not be formed to protrude more than the main metal layer 433 in a lateral direction (e.g., -x direction or +x direction). Since the first protective layer 490 formed on the second protective layer forming layer 480 includes Ti and Cu, the first protective layer 490 may be etched faster than the second protective layer forming layer 480. In addition, the oxidized metal layer forming layer 495 may include TiO _x And CuO _x . In this case, the oxidized metal layer forming layer 495 may include only TiO than the oxidized metal layer forming layer 495 _x Is etched quickly. Further, since the oxidized metal layer forming layer 495 is located at the uppermost portion and the area contacting the etchant is large when patterning is performed, the oxidized metal layer forming layer 495 can be rapidly etched. Accordingly, the first protective layer forming layer 490 and the metal oxide layer forming layer 495 formed on the second protective layer forming layer 480 may be etched faster than the second protective layer forming layer 480.

Fig. 17 is a view for explaining a portion of the second protective layer forming layer 480 that contacts an etchant when patterning is performed. When patterning is performed, a photoresist PR may be disposed on the oxidized metal layer forming layer 495. The main metal layer forming layer 470 may be etched faster than the second protective layer forming layer 480. Accordingly, in the case where the first protective layer forming layer 490 and the metal oxide layer forming layer 495 formed on the second protective layer forming layer 480 are etched faster than the second protective layer forming layer 480, side surfaces of the second protective layer forming layer 480 and upper and lower surfaces adjacent to the side surfaces may contact the etchant, as shown in fig. 17. That is, the second protective layer forming layer 480 may contact the etchant on three surfaces. In this case, the second protective layer formation layer 480 may be etched faster than in the case where the second protective layer formation layer 480 contacts the etchant on both surfaces.

In the case where the first protective layer forming layer 490 and the metal oxide layer forming layer 495 formed over the second protective layer forming layer 480 are etched slower than the second protective layer forming layer 480, the second protective layer forming layer 480 may be contacted with an etchant on both surfaces. That is, the second protective layer forming layer 480 may contact the etchant only on a side surface of the second protective layer forming layer 480 and a lower surface adjacent to the side surface.

In contrast, in the display device 2 according to the embodiment, the first protective layer forming layer 490 and the metal oxide layer forming layer 495 formed on the second protective layer forming layer 480 may be etched faster than the second protective layer forming layer 480. Accordingly, since the second protective layer 435 is rapidly etched, the second protective layer 435 may not be formed to protrude more than the main metal layer 433 in a lateral direction (e.g., -x direction or +x direction). Accordingly, the step coverage of the third insulating layer IL3 is not reduced. Since no crack occurs in the third insulating layer IL3, the electrical characteristics and the like of the display device 2 are not deteriorated.

According to the embodiments, a display device including a high-quality connection electrode without deterioration in electrical characteristics when the connection electrode is not damaged during a subsequent process after the connection electrode is formed can be realized. However, the scope of the present disclosure is not limited by this effect.

It should be understood that the embodiments described herein should be considered in descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should generally be considered as available for other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.

Claims

1. A display device, comprising:

a substrate including a display region and a peripheral region outside the display region;

a display element arranged in the display area;

a transistor including a semiconductor layer and a gate electrode; and

a connection electrode electrically connected to the transistor and having a multilayer structure,

wherein, the connection electrode includes:

a main metal layer including a first metal element; and

and a protective layer disposed on the main metal layer and including the first metal element and a second metal element different from the first metal element.

2. The display device according to claim 1, wherein the first metal element includes at least one of copper, aluminum, platinum, silver, gold, and nickel.

3. The display device according to claim 2, wherein the second metal element includes at least one of titanium, molybdenum, and tungsten.

4. A display device according to claim 3, wherein the protective layer comprises an alloy of copper and titanium.

5. The display device according to claim 1, further comprising:

and a metal oxide layer disposed on the protective layer and including a metal oxide containing the first metal element and the second metal element.

6. The display device according to claim 1, further comprising:

and the auxiliary layer is arranged below the main metal layer.

7. The display device according to claim 6, wherein the auxiliary layer includes the second metal element.

8. The display device according to claim 7, wherein the auxiliary layer includes an auxiliary layer tip protruding more than the main metal layer in a lateral direction at a boundary between the auxiliary layer and the main metal layer.

9. The display device according to claim 7, wherein the auxiliary layer further comprises the first metal element.

10. The display device according to any one of claims 1 to 9, wherein the semiconductor layer is provided over the substrate,

The gate electrode is disposed on a gate insulating layer disposed on the semiconductor layer, and

the connection electrode is electrically connected to the semiconductor layer.

11. A display device, comprising:

a display element arranged in the display area;

a transistor including a semiconductor layer and a gate electrode; and

wherein, the connection electrode includes:

a main metal layer including a first metal element;

a first protective layer disposed over the main metal layer and including the first metal element and a second metal element different from the first metal element; and

and a second protective layer disposed between the main metal layer and the first protective layer and including the second metal element.

12. The display device according to claim 11, wherein the first metal element comprises at least one of copper, aluminum, platinum, silver, gold, and nickel.

13. The display device according to claim 12, wherein the second metal element comprises at least one of titanium, molybdenum, and tungsten.

14. The display device of claim 13, wherein the first protective layer comprises an alloy of copper and titanium.

15. The display device according to claim 11, further comprising:

and a metal oxide layer disposed on the first protective layer and including a metal oxide containing the first metal element and the second metal element.

16. The display device according to claim 11, further comprising:

and the auxiliary layer is arranged below the main metal layer.

17. The display device according to claim 16, wherein the auxiliary layer includes the second metal element.

18. The display device of claim 17, wherein the auxiliary layer comprises an auxiliary layer tip protruding in a lateral direction than the main metal layer at a boundary between the auxiliary layer and the main metal layer.

19. The display device according to claim 17, wherein the auxiliary layer further comprises the first metal element.

20. The display device according to any one of claims 11 to 19, wherein the semiconductor layer is provided over the substrate,

The connection electrode is electrically connected to the semiconductor layer.