Patent Description:
With the development of the display field representing various electrical signal information, various flat panel display apparatuses having excellent characteristics such as slimness, lightweight, and low power consumption have been researched and developed. Among them, organic light emitting display apparatuses have attracted attention as next-generation display apparatuses due to their advantages such as wide viewing angle and fast response time as well as lightweight and slimness.

Moreover, as the display area of display apparatuses gradually increases, various lines and electrodes included in the display apparatuses may be formed of a material having low resistivity.

<CIT> discloses an etchant that includes about <NUM> wt % to about <NUM> wt % of nitric acid, about <NUM> wt % to about <NUM> wt % of alkylsulfonic acid, about <NUM> wt % to about <NUM> wt % of a sulfate, about <NUM> wt % to about <NUM> wt % of an organic acid, about <NUM> wt % to about <NUM> wt % of an organic acid salt, and a balance of water.

<CIT> discloses an etchant composition that includes: <NUM> wt % to <NUM> wt % of a first organic acid compound; <NUM> wt % to <NUM> wt % of a second organic acid compound; <NUM> wt % to <NUM> wt % of an inorganic acid compound; <NUM> wt % to <NUM> wt % of a sulfonic acid compound; <NUM> wt % to <NUM> wt % of a hydrogen sulfate salt compound; <NUM> wt % to <NUM> wt % of a nitrogen-containing dicarbonyl compound; <NUM> wt % to <NUM> wt % of an amino acid derivative compound; <NUM> wt % to <NUM> wt % of an iron-containing oxidizing agent compound; and a balance amount of water.

<CIT> discloses an etchant composition that comprises: anion of an organic acid compound; anion of a sulfonic acid compound; nitrate ions; sulfate ions; a dicarbonyl compound including nitrogen; and remaining water, wherein the anion content of the organic acid compound is <NUM> to <NUM> wt%.

<CIT> discloses an etching solution composition that contains, relative to the total weight of the composition, (A) <NUM> to <NUM>% by weight of nitric acid; (B-<NUM>) <NUM> to <NUM>% by weight of alkylsulfonic acid having <NUM> to <NUM> carbon atoms;(B-<NUM>) <NUM> to <NUM>% by weight of organic acids other than alkylsulfonic acid; (C) <NUM> to <NUM>% by weight of the salt of the organic acid; (D) <NUM> to <NUM>% by weight of the sulfate; and (E) the balance of water, the (D) sulfate comprises more than one selected from the group consisting of potassium hydrogen sulfate, sodium hydrogen sulfate, and magnesium sulfate.

Aspects of the present disclosure are directed towards an etchant composition capable of etching a multi-layer structure including silver and a method of manufacturing a display apparatus by using the etchant composition.

According to an aspect, there is provided an etchant composition as set out in claim <NUM>. Additional features are provided in claims <NUM> to <NUM>.

According to another aspect, there is provided method as set out in claim <NUM>. Additional features are provided in claims <NUM> to <NUM>.

The etchant composition may be used to etch the first conductive layer and the second conductive layer.

The method may further include forming a line layer in the non-display area, wherein the electrode layer may be etched by the etchant composition with the line layer exposed.

The line layer may include a first line layer including a second metal, a second line layer including a third metal, and a third line layer including the second metal.

The second metal may be titanium, and the third metal may be aluminum.

The thin film transistor may include a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and the line layer may be formed of the same material as the source electrode or the drain electrode.

The method may further include forming an intermediate layer on the pixel electrode and an opposite electrode on the intermediate layer.

The inorganic acid compound may include a nitric acid.

The sulfonic acid compound may include at least one of a methanesulfonic acid, an ethanesulfonic acid, or a propanesulfonic acid.

In the present invention, the sulfate compound comprises at least one of a potassium hydrogen sulfate, a sodium hydrogen sulfate, or an ammonium hydrogen sulfate.

In the present invention, the organic acid compound comprises at least one of an acetic acid, a citric acid, a glycolic acid, a malonic acid, a lactic acid, or a tartaric acid.

In the present invention, the metal or metal salt comprises at least one of a ferric nitrate, a ferric sulfate, a copper, a copper sulfate, or an iron.

In the etchant composition, a wt% ratio of the sulfate compound to the organic acid compound may be about <NUM>:<NUM> to about <NUM>:<NUM>.

The water may be about <NUM> wt% to about <NUM> wt%.

Other aspects, features, and advantages other than those described above will become apparent from the following detailed description, the appended claims, and the accompanying drawings.

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

Throughout the present disclosure, the expression "at least one of a, b or c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

The present disclosure may include various embodiments and modifications, and certain embodiments thereof are illustrated in the drawings and will be described herein in detail. The effects and features of the present disclosure and the accomplishing methods thereof will become apparent from the embodiments described below in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments described below and may be embodied in various modes.

It will be understood that although terms such as "first" and "second" may be used herein to describe various components, these components should not be limited by these terms and these terms are only used to distinguish one component from another component.

Also, it will be understood that the terms "comprise," "include," and "have" used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

It will be understood that when a layer, region, or component is referred to as being "on" another layer, region, or component, it may be "directly on" the other layer, region, or component or may be "indirectly on" the other layer, region, or component with one or more intervening layers, regions, or components therebetween.

Sizes of components in the drawings may be exaggerated for convenience of description. In other words, because the sizes and thicknesses of components in the drawings are arbitrarily illustrated for convenience of description, embodiments of the present disclosure are not limited thereto.

As used herein, "A and/or B" represents the case of A, B, or A and B. In the following embodiments, a line "extending in a first direction or a second direction" may include not only extending in a linear shape but also extending in a zigzag or curved shape along the first direction or the second direction.

In the following embodiments, when referred to as "in a plan view," it may mean that a target portion is viewed from above, and when referred to as "in a cross-sectional view," it may mean that a cross-section of a target portion vertically cut is viewed from side. In the following embodiments, when referred to as "overlapping," it may include overlapping "in a plan view" and overlapping "in a cross-sectional view.

Any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed within the recited range. For example, a range of "<NUM> to <NUM>" is intended to include all subranges between (and including) the recited minimum value of <NUM> and the recited maximum value of <NUM>, that is, having a minimum value equal to or greater than <NUM> and a maximum value equal to or less than <NUM>, such as, for example, <NUM> to <NUM>. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein.

Further, the use of "may" when describing embodiments of the present disclosure refers to "one or more embodiments of the present disclosure".

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, and in the following description, like reference numerals will denote like elements.

<FIG> is a perspective view schematically illustrating a display apparatus according to an embodiment.

Referring to <FIG>, a display apparatus <NUM> may include a display area DA and a non-display area NDA arranged around the display area DA. The non-display area NDA may surround the display area DA. The display apparatus <NUM> may provide an image by using light emitted from a plurality of pixels P arranged in the display area DA, and the non-display area NDA may be an area where no image is displayed. For example, a plurality of pixels P may not be arranged in the non-display area NDA to provide an image.

Hereinafter, an organic light emitting display apparatus will be described as an example of the display apparatus <NUM> according to an embodiment. However, the display apparatus <NUM> of embodiments of the present disclosure is not limited thereto. In an embodiment, the display apparatus <NUM> of the present disclosure may be an inorganic light emitting display apparatus (or an inorganic electroluminescence (EL) display apparatus) or may be another display apparatus <NUM> such as a quantum dot light emitting display apparatus. For example, an emission layer of a display element included in the display apparatus <NUM> may include an organic material, an inorganic material, quantum dots, an organic material and quantum dots, and/or an inorganic material and quantum dots.

Although <FIG> illustrates the display apparatus <NUM> having a flat display surface, embodiments of the present disclosure are not limited thereto. In an embodiment, the display apparatus <NUM> may include a three-dimensional display surface or a curved display surface.

When the display apparatus <NUM> includes a three-dimensional display surface, the display apparatus <NUM> may include a plurality of display areas indicating different directions (e.g., display areas facing different directions) and may include, for example, a polygonal columnar display surface. In an embodiment, when the display apparatus <NUM> includes a curved display surface, the display apparatus <NUM> may be implemented (or provided) in various suitable forms such as flexible, foldable, and/or rollable forms corresponding to flexible, foldable, and/or rollable display apparatuses respectively.

<FIG> illustrates the display apparatus <NUM> that may be applied to a mobile phone terminal. However, embodiments of the present disclosure are not limited thereto. For example, a mobile phone terminal may be constructed by arranging electronic modules, a camera module, a power module, and the like mounted on a main board, in a bracket/case or the like together with (e.g., housed with) the display apparatus <NUM>. The display apparatus <NUM> according to the present disclosure may be applied to large electronic apparatuses (e.g., televisions or monitors) and small and medium electronic apparatuses (e.g., tablets, car navigations, game machines, or smart watches).

Although <FIG> illustrates a case where the display area DA of the display apparatus <NUM> is a tetragonal shape, the shape of the display area DA may be any suitable shape including, for example, circular, elliptical, or polygonal (e.g., triangular or pentagonal) shapes.

The display apparatus <NUM> may include a plurality of pixels P arranged in the display area DA. Each of the pixels P may include an organic light emitting diode OLED. Each pixel P may emit, for example, red, green, blue, or white light from the organic light emitting diode OLED. As used herein, the "pixel P" may be understood as a pixel emitting any one of red light, green light, blue light, and white light.

<FIG> is a plan view schematically illustrating a display apparatus according to an embodiment.

Referring to <FIG>, the display apparatus <NUM> may include a plurality of pixels P arranged in the display area DA. Each of the pixels P may include a display element such as an organic light emitting diode OLED. Each pixel P may emit, for example, red, green, blue, or white light from the organic light emitting diode OLED. As used herein, the "pixel P" may be understood as a pixel emitting any one of red light, green light, blue light, and white light.

Each pixel P may be connected (e.g., electrically connected) to peripheral circuits arranged in the non-display area NDA. A first scan driving circuit <NUM>, a first emission driving circuit <NUM>, a second scan driving circuit <NUM>, a terminal <NUM>, a data driving circuit <NUM>, a first power supply line <NUM>, and a second power supply line <NUM> may be arranged in the non-display area NDA.

The first scan driving circuit <NUM> may provide a scan signal to each pixel P through a scan line SL. The first emission driving circuit <NUM> may provide an emission control signal to each pixel P through an emission control line EL. The second scan driving circuit <NUM> may be arranged parallel to the first scan driving circuit <NUM> with the display area DA therebetween. Some of the pixels P arranged in the display area DA may be connected (e.g., electrically connected) to the first scan driving circuit <NUM>, and the others may be connected (e.g., electrically connected) to the second scan driving circuit <NUM>. In an embodiment, the second scan driving circuit <NUM> may be omitted.

The first emission driving circuit <NUM> may be arranged on or in the non-display area NDA while being spaced apart from the first scan driving circuit <NUM> in the x direction. Also, in an embodiment, the first emission driving circuit <NUM> may be arranged alternately in the y direction with the first scan driving circuit <NUM>. For example, the first emission driving circuit <NUM> may be alternately arranged and spaced apart from the first scan driving circuit <NUM> in the y direction.

The terminal <NUM> may be arranged at one side of a substrate <NUM>. The terminal <NUM> may be exposed, by not being covered by an insulating layer, and be connected (e.g., electrically connected) to a printed circuit board PCB. For example, a contact of the terminal <NUM> may be exposed to connect (e.g., electrically connect) to the printed circuit board PCB (e.g., a terminal PCB-P of the printed circuit board PCB). A terminal PCB-P of the printed circuit board PCB may be connected (e.g., electrically connected) to the terminal <NUM> of the display apparatus <NUM>. The printed circuit board PCB may be configured to transmit power or signals of a controller to the display apparatus <NUM>. A control signal generated by the controller may be transmitted to each of the first scan driving circuit <NUM>, the first emission driving circuit <NUM>, and the second scan driving circuit <NUM> through the printed circuit board PCB. The controller may provide a first power voltage ELVDD and a second power voltage ELVSS to the first power supply line <NUM> and the second power supply line <NUM> through a first connection line <NUM> and a second connection line <NUM>, respectively. The first power voltage ELVDD may be provided to each pixel P through a driving voltage line PL connected to the first power supply line <NUM>, and the second power voltage ELVSS may be provided to an opposite electrode of each pixel P connected to the second power supply line <NUM>. For example, the first power voltage ELVDD may be a driving voltage, and the second power voltage ELVSS may be a common voltage.

The data driving circuit <NUM> may be connected (e.g., electrically connected) to a data line DL. A data signal of the data driving circuit <NUM> may be provided to each pixel P through a connection line <NUM> connected to the terminal <NUM> and a data line DL connected to the connection line <NUM>.

<FIG> illustrates that the data driving circuit <NUM> is arranged on the printed circuit board PCB. However, in an embodiment, the data driving circuit <NUM> may be arranged on the substrate <NUM>. For example, the data driving circuit <NUM> may be arranged between the terminal <NUM> and the first power supply line <NUM> on the substrate <NUM>.

The first power supply line <NUM> may include a first subline <NUM> and a second subline <NUM> extending in parallel in the x direction with the display area DA therebetween. The second power supply line <NUM> may partially surround the display area DA in a loop shape with one side open. In an embodiment, the terminal <NUM> may be at the one open side of the loop shape of the second power supply line <NUM>.

<FIG> are cross-sectional views schematically illustrating a method of manufacturing a display apparatus, according to an embodiment.

Hereinafter, a method of manufacturing a display apparatus will be sequentially described with reference to <FIG>.

A method of manufacturing a display apparatus, according to an embodiment, may include an operation of forming a thin film transistor TFT on a substrate <NUM> of a display area DA, an operation of forming a planarization layer <NUM> on the thin film transistor TFT, an operation of forming an electrode layer <NUM> on the planarization layer <NUM>, and an operation of forming a pixel electrode <NUM> by etching the electrode layer <NUM> with an etchant composition.

Referring to <FIG>, an operation of forming a thin film transistor TFT on the substrate <NUM> of the display area DA may be performed. The substrate <NUM> may include a glass material, a ceramic material, a metal material, and/or any flexible or bendable material. When the substrate <NUM> is flexible or bendable, the substrate <NUM> may include a polymer resin such as polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, and/or cellulose acetate propionate. The substrate <NUM> may have a single-layer or multi-layer structure of the above-mentioned material, and in the case of the multi-layer structure, the substrate may further include an inorganic layer. In an embodiment, the substrate <NUM> may have an organic/inorganic/organic structure.

A buffer layer <NUM> may be formed on the substrate <NUM>. The buffer layer <NUM> may be on the substrate <NUM> to reduce or block the penetration of foreign materials, moisture, or external air from the bottom of the substrate <NUM>. The buffer layer <NUM> may provide a flat surface on the substrate <NUM>. The buffer layer <NUM> may include an inorganic material (e.g., oxide or nitride), an organic material, or an organic/inorganic composite and may include a single-layer or multi-layer structure of an inorganic material and an organic material.

A thin film transistor TFT may be formed on the buffer layer <NUM>. The thin film transistor TFT may include a semiconductor layer <NUM>, a gate electrode <NUM>, a source electrode <NUM>, and a drain electrode <NUM>. The thin film transistor TFT may be connected (e.g., electrically connected) to an organic light emitting diode OLED described in more detail below to drive the organic light emitting diode OLED.

The semiconductor layer <NUM> may include a channel area <NUM> formed on the buffer layer <NUM> and overlapping the gate electrode <NUM>. The semiconductor layer <NUM> may include a source area <NUM> and a drain area <NUM> arranged on respective sides of the channel area <NUM>. The source area <NUM> and the drain area <NUM> may each include a higher concentration of impurities than the channel area <NUM>. Here, the impurities may include N-type impurities or P-type impurities. The source area <NUM> and the drain area <NUM> may be electrically and respectively connected to the source electrode <NUM> and the drain electrode <NUM> described in more detail below. For example, the source area <NUM> may be connected (e.g., electrically connected) to the source electrode <NUM>, and the drain area <NUM> may be connected (e.g., electrically connected) to the drain electrode <NUM>. The source area <NUM> may overlap the source electrode <NUM> in the z direction, and the drain area <NUM> may overlap the drain electrode <NUM> in the z direction.

The semiconductor layer <NUM> may include an oxide semiconductor and/or a silicon semiconductor. When the semiconductor layer <NUM> includes an oxide semiconductor, the semiconductor layer <NUM> may include, for example, an oxide of at least one of indium (In), gallium (Ga), stannum (Sn), zirconium (Zr), vanadium (V), hafnium (Hf), cadmium (Cd), germanium (Ge), chromium (Cr), titanium (Ti), or zinc (Zn). For example, the semiconductor layer <NUM> may include InSnZnO (ITZO) or InGaZnO (IGZO). When the semiconductor layer <NUM> includes a silicon semiconductor, the semiconductor layer <NUM> may include, for example, amorphous silicon (a-Si) or low temperature poly-silicon (LTPS) crystallized from amorphous silicon (a-Si).

A first insulating layer <NUM> may be formed on the semiconductor layer <NUM>. The first insulating layer <NUM> may include an inorganic insulating material of at least one of silicon oxide (SiO<NUM>), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al<NUM>O<NUM>), titanium oxide (TiO<NUM>), tantalum oxide (Ta<NUM>O<NUM>), hafnium oxide (HfO<NUM>), or zinc oxide (ZnO<NUM>). The first insulating layer <NUM> may include a single-layer or a multi-layer structure including the above-mentioned inorganic insulating material.

The gate electrode <NUM> may be formed on the first insulating layer <NUM>. The gate electrode <NUM> may include a single-layer or a multi-layer structure formed of 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), titanium (Ti), tungsten (W), or copper (Cu). The gate electrode <NUM> may be connected to a gate line such that an electrical signal may be applied to the gate electrode <NUM>.

A second insulating layer <NUM> may be formed on the gate electrode <NUM>. The second insulating layer <NUM> may include an inorganic insulating material of at least one of silicon oxide (SiO<NUM>), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al<NUM>O<NUM>), titanium oxide (TiO<NUM>), tantalum oxide (Ta<NUM>O<NUM>), hafnium oxide (HfO<NUM>), or zinc oxide (ZnO<NUM>). The second insulating layer <NUM> may include a single-layer or a multi-layer structure including the above-mentioned inorganic insulating material.

A storage capacitor Cst may be formed on the first insulating layer <NUM>. The storage capacitor Cst may include a lower electrode <NUM> and an upper electrode <NUM> overlapping (e.g., overlapping in the z direction or in a plan view) the lower electrode <NUM>. The lower electrode <NUM> and the upper electrode <NUM> of the storage capacitor Cst may overlap each other with the second insulating layer <NUM> therebetween. In other words, the lower electrode <NUM> and the upper electrode <NUM> of the storage capacitor Cst may overlap each other in the z direction (or in the plan view) and the second insulating layer <NUM> may be between the lower electrode <NUM> and the upper electrode <NUM> in the z-direction (or in the plan view).

In an embodiment, the lower electrode <NUM> of the storage capacitor Cst may overlap the gate electrode <NUM> of the thin film transistor TFT, and the lower electrode <NUM> of the storage capacitor Cst may be integrally provided with the gate electrode <NUM> of the thin film transistor TFT.

The upper electrode <NUM> of the storage capacitor Cst may include 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), titanium (Ti), tungsten (W), and/or copper (Cu) and may include a single-layer or a multi-layer structure of the above-mentioned material.

A third insulating layer <NUM> may be formed on the upper electrode <NUM> of the storage capacitor Cst. The third insulating layer <NUM> may include an inorganic insulating material of at least one of silicon oxide (SiO<NUM>), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al<NUM>O<NUM>), titanium oxide (TiO<NUM>), tantalum oxide (Ta<NUM>O<NUM>), hafnium oxide (HfO<NUM>), or zinc oxide (ZnO<NUM>). The third insulating layer <NUM> may include a single-layer or a multi-layer structure including the above-mentioned inorganic insulating material.

The source electrode <NUM> and the drain electrode <NUM> may be formed on the third insulating layer <NUM>. The source electrode <NUM> and the drain electrode <NUM> may include a conductive material including molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), or the like and may include a single-layer or a multi-layer structure including the above-mentioned material. The source electrode <NUM> and the drain electrode <NUM> may include a multi-layer structure of Ti/Al/Ti.

When the source electrode <NUM> and the drain electrode <NUM> are formed on the third insulating layer <NUM> of the display area DA, a line layer <NUM> may be formed on the third insulating layer <NUM> of the non-display area NDA by the same process. The line layer <NUM> may include the same material as the source electrode <NUM> or the drain electrode <NUM>. The line layer <NUM> may include a first line layer 139a including a second metal, a second line layer 139b including a third metal, and a third line layer 139c including the second metal. The second metal and the third metal may include molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), or the like. For example, the second metal may include titanium (Ti), and the third metal may include aluminum (Al). Thus, the line layer <NUM> may have a titanium (Ti)/aluminum (Al)/titanium (Ti) multi-layer structure.

Lines arranged on the same layer as the semiconductor layer <NUM>, the gate electrode <NUM>, and the upper electrode <NUM> of the display area DA may be arranged under the line layer <NUM>, but are omitted for convenience of description. The electrode layer <NUM> described in more detail below may be etched by an etchant composition with the top surface of the line layer <NUM> exposed.

Referring to <FIG>, after the operation of forming the thin film transistor TFT on the substrate <NUM> of the display area DA, an operation of forming a planarization layer <NUM> on the thin film transistor TFT may be further performed.

The planarization layer <NUM> may be formed on the source electrode <NUM> and the drain electrode <NUM>. The planarization layer <NUM> may include a single-layer or a multi-layer structure formed of an organic material or an inorganic material. In an embodiment, the planarization layer <NUM> may include a general-purpose polymer such as benzocyclobutene (BCB), polyimide (PI), hexamethyldisiloxane (HMDSO), polymethylmethacrylate (PMMA), or polystyrene (PS), a polymer derivative having a phenolic group, an acrylic polymer, an imide-based polymer, an arylether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, a vinyl alcohol-based polymer, or any blend thereof. The planarization layer <NUM> may include silicon oxide (SiO<NUM>), silicon nitride (SiNx), silicon oxynitride (SiON), aluminum oxide (Al<NUM>O<NUM>), titanium oxide (TiO<NUM>), tantalum oxide (Ta<NUM>O<NUM>), and hafnium oxide (HfO<NUM>), or zinc oxide (ZnO<NUM>). After the forming of the planarization layer <NUM>, chemical mechanical polishing may be performed to provide a flat upper surface. In an embodiment, a contact metal layer may be formed on the planarization layer <NUM>, and a planarization layer may be additionally formed on the contact metal layer.

Referring to <FIG>, after the operation of forming the planarization layer <NUM> on the thin film transistor TFT, an operation of forming an electrode layer <NUM> on the planarization layer <NUM> may be further performed. The electrode layer <NUM> may include a reflective layer formed 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), titanium (Ti), tungsten (W), copper (Cu), or any compound thereof and a transparent or semitransparent conductive layer formed on the reflective layer. The transparent or semitransparent electrode may include at least one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In<NUM>O<NUM>), indium gallium oxide (IGO), or aluminum zinc oxide (AZO). In an embodiment, the electrode layer <NUM> may include a first conductive layer 180a, a second conductive layer 180b including a first metal and arranged on the first conductive layer 180a, and a third conductive layer 180c arranged on the second conductive layer 180b. For example, the first conductive layer 180a and the third conductive layer 180c may include an indium tin oxide (ITO) that is a transparent or semitransparent conductive layer, and the first metal may include silver (Ag). Thus, in this case, the electrode layer <NUM> may include a stack structure of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO).

Referring to <FIG> and <FIG>, after the operation of forming the electrode layer <NUM> on the planarization layer <NUM>, an operation of forming a pixel electrode <NUM> by etching the electrode layer <NUM> with an etchant composition may be further performed.

In an embodiment, in the operation of forming the pixel electrode <NUM> by etching the electrode layer <NUM> with the etchant composition, a photoresist pattern PR may be patterned on the electrode layer <NUM> and then the pixel electrode <NUM> may be formed by etching the electrode layer <NUM> by using the above-mentioned etchant composition. In other words, the photoresist pattern PR may be patterned on the electrode layer <NUM> prior to applying the etchant composition to form the pixel electrode <NUM> by etching the electrode layer <NUM>.

The pixel electrode <NUM> may include a first layer 210a, a second layer 210b, and a third layer 210c. The first layer 210a, the second layer 210b, and the third layer 210c of the pixel electrode <NUM> may respectively correspond to the first conductive layer 180a, the second conductive layer 180b, and the third conductive layer 180c of the electrode layer <NUM>. For example, the first layer 210a, the second layer 210b, and the third layer 210c may be formed by etching the first conductive layer 180a, the second conductive layer 180b, and the third conductive layer 180c respectively. In an embodiment, the first layer 210a and the third layer 210c of the pixel electrode <NUM> may include indium tin oxide (ITO), and the second layer 210b may include silver (Ag). In this case, the pixel electrode <NUM> may include a stack structure of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO).

Accordingly, the pixel electrode <NUM> may be formed by etching the electrode layer <NUM> including, in an embodiment, a multi-layer structure such as indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO) by using an etchant composition according to an embodiment.

Various lines and electrodes included in the display apparatus may include silver (Ag). However, because a line or electrode including silver (Ag) has a weak bonding strength with a layer or film located over or under (e.g., directly on) the line or electrode include silver (Ag), the line or electrode may include a multi-layer structure including a stack of a layer including silver (Ag) and other conductive layers. For example, the stack may include silver (Ag) between other conductive layers.

Also, various lines and electrodes included in the display apparatus may be formed by using a patterning process such as photolithography including an etching process, and when the lines or electrodes include multiple layers having different properties, there may be a limit in forming lines or electrodes having desired or suitable characteristics by a concurrent (e.g., simultaneous) etching process. In addition, because an etchant of the related art used to etch a line may include phosphoric acid, other lines in a display apparatus may be damaged by the phosphoric acid during the etching process and silver ions may be reduced and precipitated through this process, and accordingly, defects may occur (or be introduced) due to silver particles. In order to prevent or reduce the occurrence of silver particles, a multi-layer structure including silver (Ag) and other conductive layers may be sequentially etched. However, the above-mentioned method (e.g., method including sequential etching) may reduce (e.g., significantly reduce) the efficiency of the manufacturing process. For example, additional processing steps or tasks may be needed which may decrease efficiency (e.g., throughput) of the manufacturing process.

The etchant composition according to an embodiment may prevent or substantially prevent silver (Ag) ions from being reduced and precipitated while collectively etching an electrode layer including a multi-layer structure such as indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO). Accordingly, the reliability of the display apparatus may be improved. Further, efficiency (e.g., throughput) may be improved compared to sequential etching.

The etchant composition according to the invention comprises an inorganic acid compound of <NUM> wt% to <NUM> wt%, a sulfonic acid compound of <NUM> wt% to <NUM> wt%, a sulfate compound of <NUM> wt% to <NUM> wt%, an organic acid compound of <NUM> wt% to <NUM> wt%, a metal or metal salt of <NUM> wt% to <NUM> wt%, and a remaining amount of water.

The inorganic acid compound may include a nitric acid. The nitric acid may be a component used as an oxidizer and may be used to etch silver (Ag) and other conductive layers. For example, the nitric acid may be used to oxidize and wet-etch silver (Ag) and other conductive layers. The content of the nitric acid may be about <NUM> wt% to about <NUM> wt% in the total weight of the etchant composition. When the content of the nitric acid exceeds about <NUM> wt%, the etch rate of the other conductive layers (e.g., a transparent or semitransparent conductive layer) may be accelerated and thus an undercut may occur in the other conductive layers located over and/or under silver (Ag), which may cause a problem in a subsequent process. When the content of the nitric acid is less than about <NUM> wt%, the etch rate of the silver (Ag) and the other conductive layers may be reduced and thus the etching uniformity may be reduced depending on the position of the substrate, which may cause a stain. Thus, when the nitric acid of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, the etch rate may be easily controlled (e.g., more easily controlled) and the silver (Ag) and the other conductive layers may be uniformly or substantially uniformly etched.

The sulfonic acid compound may be used as an etchant for etching the silver (Ag) and conductive layers oxidized with the nitric acid. The sulfonic acid compound may maintain a constant or substantially constant etch rate by reducing the decomposition rate of the nitric acid. The content of the sulfonic acid compound may be about <NUM> wt% to about <NUM> wt% in the total weight of the etchant composition. When the content of the sulfonic acid compound is high, because the etch rate of the silver (Ag) may become too high, a tip may occur in the conductive layers located over and/or under the silver (Ag) or a line defect may occur due to the over-etching of silver (Ag). When the content of the sulfonic acid compound is low, the effect of inhibiting the decomposition of the nitric acid may be reduced and thus the stability may be reduced and a silver (Ag) residue may occur. Thus, when the sulfonic acid compound of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, the etch rate of the silver (Ag) and conductive layers may be easily controlled and a defect due to the occurrence of a silver (Ag) residue and silver (Ag) resorption may be prevented or substantially prevented.

The sulfate compound comprises at least one of a potassium hydrogen sulfate, a sodium hydrogen sulfate, or an ammonium hydrogen sulfate.

The sulfate compound may be used as an etchant for etching the conductive layer. The sulfate compound may cause an etch stop of silver (Ag). In this case, the etch stop may mean that a skew, which is the distance between the photoresist pattern end and the silver (Ag) end, may not increase even when time elapses (e.g., additional time elapses where the silver (Ag) is exposed to the etchant composition including the sulfate compound). Thus, even when the etching time increases in the etching process, an increase of the side etch of silver (Ag) may be prevented or substantially prevented. That is, because the etchant composition according to an embodiment includes a sulfate compound, the etch stop characteristics may be implemented and the etch rate may be controlled and accordingly the side etch may be controlled.

The content of the sulfate compound may be about <NUM> wt% to about <NUM> wt% in the total weight of the etchant composition. When the content of the sulfate compound is higher than about <NUM> wt%, the etch rate of the conductive layer may be too high and thus a corrosion failure may be induced. When the content of the sulfate compound is lower than about <NUM> wt%, the etch rate of the conductive layer may decrease and thus a residue of silver (Ag) and the other conductive layers may occur. Thus, when the sulfate compound of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, the etch rate may be easily controlled and the etch stop characteristics may be implemented and thus the silver (Ag) and the other conductive layers may be uniformly etched.

The organic acid compound comprises at least one of an acetic acid, a citric acid, a glycolic acid, a malonic acid, a lactic acid, or a tartaric acid. For example, the organic acid compound may include an acetic acid and a citric acid.

The organic acid compound may be used as an etchant for etching the silver (Ag). The organic acid compound may be used to etch the silver (Ag) oxidized by the nitric acid described above.

The content of the organic acid compound may be about <NUM> wt% to about <NUM> wt% in the total weight of the etchant composition. When the content of the organic acid compound is less than about <NUM> wt%, a stain may occur due to a non-uniform etch rate depending on the position of the substrate. When the content of the organic acid compound is more than about <NUM> wt%, an over-etching problem may occur. Thus, when the organic acid compound of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, the etch rate of silver (Ag) may be controlled (e.g., easily controlled) and a defect due to the occurrence of a silver (Ag) residue and resorption may be prevented or be substantially prevent.

The metal or metal salt comprises at least one of a ferric nitrate, a ferric sulfate, copper, a copper sulfate, or iron.

The metal or metal salt may be used as an oxidizer of silver (Ag). The metal or metal salt may be used as an auxiliary oxidizer of the nitric acid described above.

The content of the metal or metal salt may be about <NUM> wt% to about <NUM> wt% in the etchant composition. When the content of the metal or metal salt is less than about <NUM>%, the etching uniformity may be reduced. When the content of the metal or metal salt is more than about <NUM> wt%, the etch stop characteristics may be degraded. Thus, when the metal or metal salt of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, the etch rate of silver (Ag) may be easily controlled, a defect due to a silver (Ag) residue and silver (Ag) resorption may be prevented or be substantially prevented, and the etch stop characteristics may be improved.

The etchant composition according to the invention comprises water. The water may be included in the etchant composition such that the sum of the wt% of components other than the water and the wt% of the water may be <NUM> wt%. Ultrapure water may be used as the water included in the etchant composition. The water included in the etchant composition may function to activate the sulfate compound.

In an embodiment, the content of the water may be about <NUM> wt% to about <NUM> wt% in the etchant composition. When the content of the water is less than about <NUM> wt%, the etch stop characteristics may be degraded. When the content of the water is more than about <NUM> wt%, there may be a problem such as the occurrence of a silver residue. Thus, when the water of about <NUM> wt% to about <NUM> wt% is included in the etchant composition, a defect due to a silver residue may be prevented or be substantially prevented and the etch stop characteristics may be implemented.

In an embodiment, the wt% ratio of the sulfate compound to the organic acid compound may be about <NUM>:<NUM> to about <NUM>:<NUM>. When the wt% ratio of the sulfate compound to the organic acid compound satisfies about <NUM>:<NUM> to about <NUM>:<NUM>, the etch stop characteristics may be maintained even when the number of treatments is accumulated as well as at initial etching, and thus the side etch may be controlled.

When the content of the metal or metal salt is maintained at about <NUM> ppm or less, and the water of about <NUM> wt% to about <NUM> wt% is included in the total weight of the etchant composition, the side etch may be more effectively controlled.

Hereinafter, an etchant composition according to an embodiment will be described with reference to Tables <NUM> and <NUM>.

The etchant compositions according to Embodiments <NUM> to <NUM> (Embodiment <NUM>, Embodiment <NUM>, Embodiment <NUM>, and Embodiment <NUM>) and Comparative Examples <NUM> to <NUM> (Comparative Example <NUM>, Comparative Example <NUM>, Comparative Example <NUM>, Comparative Example <NUM>, Comparative Example <NUM>, Comparative Example <NUM>, and Comparative Example <NUM>) were manufactured as illustrated in Table <NUM> below. The % in Table <NUM> below may be wt%.

Comparative Example <NUM> and Comparative Example <NUM> may respectively correspond to the cases where the ratio of the sulfate compound to the organic acid compound is about <NUM>:<NUM> and about <NUM>:<NUM> deviating from a weight ratio of about <NUM>:<NUM> to about <NUM>:<NUM>, Comparative Example <NUM> may correspond to the case where the content of the organic acid compound is less than about <NUM> wt% and the content of the sulfate compound is less than about <NUM> wt%, and Comparative Example <NUM> may correspond to the case where the content of the organic acid compound is more than about <NUM> wt%. Also, Comparative Example <NUM> may correspond to the case where no metal or metal salt is added, Comparative Example <NUM> may correspond to the case where the content of the metal or metal salt is more than about <NUM> wt%, and Comparative Example <NUM> may correspond to the case where the content of the water is less than about <NUM> wt%.

After forming a multi-layer structure (e.g., triple layer) of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO) on a substrate and producing a specimen by patterning a photoresist on the triple layer, an etching process was performed by using a first etchant and a second etchant. In this case, the first etchant may correspond to the etchant composition of Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>, and the second etchant may correspond to the etchant obtained by dissolving silver powders in the etchant composition of Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>, assuming that an etching process was performed for a long time.

After the first etchant and the second etchant were inserted into the spray-etching test equipment (Model name: ETCHER(TFT), SEMES) and the temperature was set to <NUM> causing a rise in temperature, an etching process was performed on the specimen when the temperature reached <NUM> ± <NUM>. The specimen was additionally over-etched by <NUM> % and <NUM> % from the time when the etching of the specimen was ended (e.g., the etching time was increased by <NUM>% and <NUM>%), and the side etch resulting from each of <NUM>% over-etching and <NUM>% over-etching was measured by using an electron scanning microscope (Model name: SU-<NUM>, HITACHI). In this case, the side etch may correspond to the distance from the end of the patterned photoresist to the etched silver (Ag).

A suitable range of the side etch may be less than about <NUM>. When the side etch exceeds about <NUM>, it may be considered or categorized as a defect. Also, the etch stop may be determined as good when the side etch change of <NUM>% over-etching compared to <NUM>% over-etching is less than about <NUM>. The etch stop may be considered as poor when the side etch change of <NUM>% over-etching compared to <NUM>% over-etching exceeds about <NUM>.

After the first etchant and the second etchant were inserted into the spray-etching test equipment (Model name: ETCHER(TFT), SEMES) and the temperature was set to <NUM> causing a rise in temperature, an etching process was performed on the specimen when the temperature reached <NUM> ± <NUM>. The total etching time was <NUM> seconds. When the <NUM>-second etching time elapsed after the specimen was inserted and spraying was started, the specimen was extracted and cleaned with deionized water and then dried by using a hot air dryer. The photoresist was then removed by using a photoresist (PR) stripper. After the cleaning and drying, the electron scanning microscope (Model name: SU-<NUM>, HITACHI) was used to measure a residue that is a phenomenon in which silver (Ag) and indium tin oxide (ITO) remain unetched in a region not covered by the photoresist (e.g., not covered by the photoresist during the etching process and prior to the photoresist being stripped by the photoresist stripper). When no residue was measured, it was evaluated as good, and when a residue was measured, it was evaluated as poor.

After the first etchant and the second etchant were inserted into the spray-etching test equipment (Model name: ETCHER(TFT), SEMES) and the temperature was set to <NUM> causing a rise in temperature, an etching process was performed on the specimen when the temperature reached <NUM> ± <NUM>. The total etching time was <NUM> seconds. When the <NUM>-second etching time elapsed after the specimen was inserted and spraying was started, the specimen was extracted and cleaned with deionized water and then dried by using a hot air dryer. After the cleaning and drying, the electron scanning microscope (Model name: SU-<NUM>, HITACHI) (Ag) was used to measure the number of silver (Ag) particles adsorbed onto the upper titanium (Ti) of the titanium (Ti)/aluminum (Al)/titanium (Ti) triple layer exposed in the specimen. In this case, when the measured number of silver (Ag) particles was about <NUM> or less, it was evaluated as good, and when the measured number of silver (Ag) particles was more than about <NUM>, it was evaluated as poor.

In Table <NUM>, O denotes good and X denotes poor. Referring to Table <NUM>, when the ratio of the sulfate compound to the organic acid compound in the etchant composition was about <NUM>:<NUM> to about <NUM>:<NUM> as in Embodiments <NUM> to <NUM>, the side etch of the etchants (the first etchant and the second etchant), the silver (Ag) and indium tin oxide (ITO) residues, and the silver (Ag) resorption characteristics satisfied the evaluation criterion. When the ratio of the sulfate compound to the organic acid compound in the etchant composition deviated from about <NUM>:<NUM> to about <NUM>:<NUM> as in Comparative Examples <NUM> and <NUM>, the etching performance was degraded and thus silver (Ag) and indium tin oxide (ITO) residues and a silver (Ag) resorption failure occurred in the first etchant and the second etchant, or the etch rate could not be controlled and thus the side etch or etch stop characteristics were also poor in the first etchant.

As in Comparative Example <NUM>, when the content ratio of the sulfate compound to the organic acid compound is satisfied but the content of the sulfate compound and the organic acid compound included in the etchant composition is small, the side etch, etch stop, silver (Ag) and indium tin oxide (ITO) residue, and silver (Ag) resorption characteristics were not satisfied.

Also, as in Comparative Example <NUM>, when the content ratio of the sulfate compound to the organic acid compound is satisfied but the content of the organic acid compound included in the etchant composition is high and the content of the water is low, there was a problem in that the solid material was not dissolved.

As in Comparative Example <NUM>, when the metal or metal salt is not included in the etchant composition, silver (Ag) and indium tin oxide (ITO) residues or a silver (Ag) resorption failure may occur in the first etchant or the second etchant.

As in Comparative Example <NUM>, when the content of the metal or metal salt included in the etchant composition exceeds about <NUM> wt%, the side etch and etch stop failure may occur.

Also, as in Comparative Example <NUM>, when the content of other materials is satisfied but the content of the water is less than about <NUM> wt%, the result of being rather poor in terms of the etch stop may be induced.

<FIG> is a diagram illustrating a state in which a metal pattern is formed by using an etchant composition according to an embodiment, and <FIG> is a diagram illustrating a state in which a metal pattern is formed after adding <NUM> ppm of silver (Ag) to an etchant composition according to an embodiment. <FIG> is a diagram illustrating a state in which a metal pattern is formed after adding <NUM> ppm of silver (Ag) to an etchant composition, in order to check the etching characteristics depending on the number of treatments of an etchant composition according to an embodiment.

Referring to <FIG>, when a metal pattern is formed by etching a thin film including a multi-layer structure of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO) by using an etchant composition according to an embodiment, it may be seen that silver (Ag) particles are effectively not or hardly precipitated.

Also, referring to <FIG>, it may be seen that silver (Ag) particles are effectively not or hardly precipitated even when the number of treatments of the etchant composition according to an embodiment is increased.

<FIG> is a graph illustrating end point detection (EPD) and skew depending on the number of treatments of an etchant composition according to an embodiment and an etchant composition according to a comparative example. More particularly, <FIG> is a graph illustrating EPD and skew depending on the number of treatments of an etchant composition according to an embodiment (Embodiment <NUM>) and an etchant composition of the related art (Comparative Example <NUM>). The etchant composition of the related art (Comparative Example <NUM>) may be an etchant composition including a phosphoric acid-based composition, and the etchant composition according to an embodiment (Embodiment <NUM>) may be an etchant composition including an inorganic acid compound of about <NUM> wt% to about <NUM> wt%, a sulfonic acid compound of about <NUM> wt% to about <NUM> wt%, a sulfate compound of about <NUM> wt% to about <NUM> wt%, an organic acid compound of about <NUM> wt% to about <NUM> wt%, a metal or metal salt of about <NUM> wt% to about <NUM> wt%, and a remaining amount of water. In this case, in order to measure the EPD and the skew depending on the number of treatments, silver (Ag) of <NUM> ppm, silver (Ag) of <NUM> ppm, silver (Ag) of <NUM> ppm, and silver (Ag) of <NUM> ppm was added to each of the etchant composition of the related art (Comparative Example <NUM>) and the etchant composition according to an embodiment (Embodiment <NUM>).

Referring to <FIG>, in the case of the etchant composition of the related art (Comparative Example <NUM>), even when the added silver (Ag) increases from <NUM> ppm to <NUM> ppm, it may be seen that the EPD satisfies a range of about <NUM> to about <NUM> and the skew satisfies about <NUM> to about <NUM>. However, in the case of the etchant composition of the related art (Comparative Example <NUM>), when the number of treatments increases, the actual number of treatments of the etchant composition of the related art (Comparative Example <NUM>) may be at most only about <NUM> due to the defect caused by silver (Ag) particles.

In the case of the etchant composition according to an embodiment (Embodiment <NUM>), even when the added silver (Ag) increases from <NUM> ppm to <NUM> ppm, it may be seen that the EPD satisfies a range of about <NUM> to about <NUM> and the skew satisfies about <NUM> to about <NUM>. That is, it may be seen that the physical properties desired for the etchant composition are maintained constant even when the concentration of silver (Ag) ions is increased as the etchant composition according to an embodiment (Embodiment <NUM>) is used multiple times. In the case of the etchant composition according to an embodiment (Embodiment <NUM>), even when the number of treatments increases, because a defect caused by silver (Ag) particles does not occur, the number of treatments may be improved by about <NUM> times compared to the etchant composition of the related art.

Also, because the etchant composition according to an embodiment (Embodiment <NUM>) has a smaller EPD than the etchant composition of the related art (Comparative Example <NUM>), when the etchant composition according to an embodiment (Embodiment <NUM>) is used, the time required for the etching process may be reduced to improve the efficiency (e.g., throughput) of the manufacturing process of the display apparatus.

However, when the etchant composition according to an embodiment is used to etch a multi-layer structure (e.g., a triple layer) of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO), a mouse bite may occur in a portion of the upper indium tin oxide (ITO) due to non-uniform formation of the upper indium tin oxide (ITO) and impurities such as dust and the silver (Ag) may be partially etched because the etchant composition permeates through a pin hole formed by the mouse bite.

Thus, according to an embodiment of the present disclosure, an etchant composition may be used to etch a multi-layer structure (e.g., a triple layer) of indium tin oxide (ITO)/silver (Ag)/indium tin oxide (ITO), wherein the upper indium tin oxide (ITO) may be etched by a separate etchant and then the silver (Ag)/indium tin oxide (ITO) may be etched by the etchant composition according to an embodiment, thereby preventing or substantially prevent a mouse bite from occurring.

In the related art, an etching process was performed by using an etchant composition including a first organic acid compound of about <NUM> wt% to about <NUM> wt%, a second organic acid compound of about <NUM> wt% to about <NUM> wt%, an inorganic acid compound of about <NUM> wt% to about <NUM> wt%, a sulfonic acid compound of about <NUM> wt% to about <NUM> wt%, a hydrogen sulfate compound of about <NUM> wt% to about <NUM> wt%, a nitrogen-containing dicarbonyl compound of about <NUM> wt% to about <NUM> wt%, an amino acid derivative compound of about <NUM> wt% to about <NUM> wt%, an iron-containing oxidizer compound of about <NUM> wt% to about <NUM> wt%, and a remaining amount of water. The etchant composition of the related art may include an iron-containing oxidizer compound of about <NUM> wt% to about <NUM> wt% to prevent or substantially prevent the occurrence of a silver (Ag) residue. However, there was a case in which an etch stop failure occurred due to the iron-containing oxidizer compound included in the etchant composition of the related art. For this purpose, the etchant composition of the related art may include a nitrogen-containing dicarbonyl compound and an amino acid derivative compound.

The nitrogen-containing dicarbonyl compound and the amino acid derivative compound included in the etchant composition of the related art may function as a corrosion inhibitor. The nitrogen-containing dicarbonyl compound and the amino acid derivative compound included in the etchant composition of the related art may form a complex compound with a metal to function as an etching controller for silver (Ag), indium tin oxide (ITO), and aluminum (Al). However, because the etch rate may be reduced due to the dicarbonyl compound and the amino acid derivative compound included in the etchant composition of the related art, a silver (Ag) residue may occur.

The etchant composition according to an embodiment may implement an etch stop by controlling the content of the sulfate compound and the water even without including the nitrogen-containing dicarbonyl compound and the amino acid derivative compound, thereby making it possible to prevent or reduce excessive etching to implement a low skew and provide a high-resolution display apparatus.

Referring to <FIG>, after the operation of forming the pixel electrode <NUM> by etching the electrode layer <NUM> with the etchant composition, an operation of forming an intermediate layer <NUM> on the pixel electrode <NUM> and an opposite electrode <NUM> on the intermediate layer <NUM> may be further performed. The pixel electrode <NUM>, the intermediate layer <NUM>, and the opposite electrode <NUM> may form an organic light emitting diode OLED.

A pixel definition layer <NUM> may be formed on the planarization layer <NUM>, and the pixel definition layer <NUM> may have an opening for exposing at least a portion of the pixel electrode <NUM>. The area exposed by the opening of the pixel definition layer <NUM> may be defined as an emission area. The periphery of emission areas may be a non-emission area, and the non-emission area may surround the emission areas. That is, the display area DA may include a plurality of emission areas and a non-emission area surrounding the emission areas. The pixel definition layer <NUM> may increase the distance between the pixel electrode <NUM> and the opposite electrode <NUM> over the pixel electrode <NUM> to prevent or substantially prevent an arc or the like from occurring at the edge of the pixel electrode <NUM>. For example, the pixel definition layer <NUM> may be formed of an organic insulating material such as polyimide, polyamide, acrylic resin, benzocyclobutene, hexamethyldisiloxane (HMDSO), or phenol resin by spin coating or the like.

The intermediate layer <NUM> may be arranged on the pixel electrode <NUM> at least partially exposed by the pixel definition layer <NUM>. The intermediate layer <NUM> may include an emission layer, and a first functional layer and a second functional layer may be selectively arranged under and over the emission layer.

In an embodiment, the intermediate layer <NUM> may be arranged on the pixel electrode <NUM> that is at least partially exposed by the pixel definition layer <NUM>. More particularly, the emission layer of the intermediate layer <NUM> may be arranged on the pixel electrode <NUM> that is at least partially exposed by the pixel definition layer <NUM>.

A first functional layer may be formed under the emission layer, and a second functional layer may be formed over the emission layer. The first functional layer and the second functional layer respectively arranged under and over the emission layer may be collectively referred to organic functional layers.

The first functional layer may include a hole injection layer (HIL) and/or a hole transport layer (HTL), and the second functional layer may include an electron transport layer (ETL) and/or an electron injection layer (EIL).

The emission layer may include an organic material including a fluorescent or phosphorescent material emitting red, green, blue, or white light. The emission layer may include a low-molecular weight organic material or a high-molecular weight organic material.

When the emission layer includes a low-molecular weight organic material, the intermediate layer <NUM> may include a structure in which a hole injection layer, a hole transport layer, an emission layer, and an electron transport layer, an electron injection layer, and the like are stacked in a single or complex structure and the low-molecular weight organic material may include various suitable organic materials such as copper phthalocyanine (CuPc), N,N'-di(naphthalene-<NUM>-yl)-N,N'-diphenyl-benzidine(NPB), and/or tris-<NUM>-hydroxyquinoline aluminum (Alq3). These layers may be formed by vacuum deposition.

When the emission layer includes a high-molecular weight organic material, the intermediate layer <NUM> may generally have a structure including a hole transport layer and an emission layer. In this case, the hole transport layer may include poly(<NUM>,<NUM>-ethylenedioxythiophene) (PEDOT) and the emission layer may include a high-molecular weight material such as poly-phenylene vinylene (PPV) and/or polyfluorene. The emission layer may be formed by screen printing, inkjet printing, laser induced thermal imaging (LITI), or the like.

The opposite electrode <NUM> may be formed on the intermediate layer <NUM>. The opposite electrode <NUM> may be formed on the intermediate layer <NUM> and may be formed to entirely cover the intermediate layer <NUM>. The opposite electrode <NUM> may be formed over the display area DA and may be formed to entirely cover the intermediate layer <NUM>. That is, by using an open mask, the opposite electrode <NUM> may be integrally formed over the entire display area to cover a plurality of pixels P arranged in the display area DA.

The opposite electrode <NUM> may include a conductive material having a low work function. For example, the opposite electrode <NUM> may include a (semi)transparent layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or any alloy thereof. Alternatively, the opposite electrode <NUM> may further include a layer such as ITO, IZO, ZnO, or In<NUM>O<NUM> on the (semi)transparent layer including the above-mentioned material.

According to an embodiment described above, an etchant may not include a phosphoric acid, and the precipitation of silver may be prevented or reduced in the process of etching a multi-layer structure including a silver layer. However, the scope of the present disclosure is not limited to these effects.

Claim 1:
An etchant composition comprising:
an inorganic acid compound of <NUM> wt% to <NUM> wt%;
a sulfonic acid compound of <NUM> wt% to <NUM> wt%;
a sulfate compound of <NUM> wt% to <NUM> wt%;
an organic acid compound of <NUM> wt% to <NUM> wt%;
a metal or metal salt of <NUM> wt% to <NUM> wt%; and
water;
wherein the sulfate compound comprises at least one of a potassium hydrogen sulfate, a sodium hydrogen sulfate, or an ammonium hydrogen sulfate;
wherein the organic acid compound comprises at least one of an acetic acid, a citric acid, a glycolic acid, a malonic acid, a lactic acid, or a tartaric acid.
wherein the metal or metal salt comprises at least one of a ferric nitrate, a ferric sulfate, copper, a copper sulfate, or iron.