Organic light emitting diode display and method for manufacturing the same

Abstract

The present disclosure relates to an organic light emitting diode (OLED) display and a method for manufacturing the same. The OLED display according to an exemplary embodiment includes: a substrate; a gate insulating layer disposed on the substrate; and a gate wiring disposed on the gate insulating layer, and the gate wiring includes a gate electrode, wherein the gate wiring includes a single layer of aluminum or an aluminum alloy, and an angle formed by a side surface of the gate wiring and the gate insulating layer is less than 65°.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2018-0104793 filed on September 3, 2018, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an organic light emitting diode (OLED) display and a method of manufacturing the same. Background Art

[0004] An organic light emitting diode (OLED) of an organic light emitting diode (OLED) display includes two electrodes and an organic emission layer disposed between the two electrodes, and electrons injected from a cathode as one electrode and holes injected from an anode as the other electrode are combined in the organic emission layer to form excitons, and the excitons emit light while emitting energy.

[0005] As technology for OLED displays has developed, OLED displays have become larger in size and higher in resolution. Therefore, problems such as signal delay or voltage drop may occur, and in order to solve the problem, the OLED display needs to be driven at a high speed.

[0006] The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept and therefore the above information may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the invention

[0007] Exemplary embodiments of the present inventive concept provide an organic light emitting diode (OLED) display that can prevent damage during a manufacturing process and can achieve high resolution and high speed driving, and a method for manufacturing the OLED display.

[0008] An OLED display according to an exemplary embodiment includes: a substrate; a gate insulating layer disposed on the substrate; and a gate wiring disposed on the gate insulating layer, and the gate wiring includes a gate electrode, wherein the gate wiring includes a single layer of aluminum or an aluminum alloy, and an angle formed by a side surface of the gate wiring and the gate insulating layer is less than 65°.

[0009] The gate insulating layer may include silicon oxide or silicon nitride.

[0010] The OLED display may further include: a semiconductor layer disposed between the substrate and the gate insulating layer; and a source electrode and a drain electrode connected to the semiconductor layer, wherein the semiconductor layer may include a channel region and the gate electrode overlaps the channel region.

[0011] The OLED display may further include: a pixel electrode connected to the drain electrode; an organic emission layer disposed on the pixel electrode; and a common electrode disposed on the organic emission layer.

[0012] The thickness of the gate wiring may be less than

[0013] The OLED display may further include a gate capping layer disposed on the gate wiring, wherein the gate capping layer may include titanium (Ti) or titanium nitride (TiN x ).

[0014] An edge of an upper surface of the gate electrode and an edge of a bottom surface of the gate cap layer may match.

[0015] According to an exemplary embodiment, a method for manufacturing an OLED display is provided. The method includes: forming a gate insulating layer on a substrate; and forming a gate wiring on the gate insulating layer; wherein forming the gate wiring includes: sequentially forming a conductive layer including aluminum or an aluminum alloy and a photoresist layer; forming a preliminary gate pattern by preliminary dry etching of the conductive layer; and forming a secondary gate pattern by secondary dry etching of the preliminary gate pattern, wherein the preliminary dry etching and the secondary dry etching use a chlorine (Cl 2 ) and nitrogen (N) mixed gas.

[0016] The mixed gas may also contain boron trichloride (BCl 3 ) or argon (Ar).

[0017] A content of nitrogen (N) in the mixed gas during the preliminary dry etching may be different from a content of nitrogen (N) in the mixed gas during the secondary dry etching.

[0018] A content of nitrogen (N) in the mixed gas during the preliminary dry etching is less than a content of nitrogen (N) in the mixed gas during the secondary dry etching.

[0019] In the preliminary dry etching, the content of nitrogen (N) in the mixed gas may be from about 10% to about 50%, and in the secondary dry etching, the content of nitrogen (N) in the mixed gas may be from about 80% to about 90%.

[0020] A taper angle of the preliminary gate pattern may exceed 65°, and a taper angle of the secondary gate pattern may be less than 65°.

[0021] The gate insulating layer may include silicon oxide or silicon nitride.

[0022] Forming the gate wiring may further include forming a preliminary photoresist pattern by exposing and developing the photoresist layer, and a width of the preliminary photoresist pattern may match a width of a bottom surface of the gate wiring.

[0023] A polymer layer including nitrogen (N) may be formed at a side surface of each of the preliminary gate pattern and the secondary gate pattern.

[0024] The thickness of the gate wiring may be less than

[0025] The method for manufacturing the OLED display may further include forming a gate capping layer on the gate wiring, wherein the gate capping layer may include titanium (Ti) or titanium nitride (TiN x ).

[0026] By using a mixture containing boron trichloride (BCl 3 ) or argon (Ar) gas is used to perform dry etching three times.

[0027] An etching selectivity ratio of the photoresist layer of the secondary dry etching to the aluminum or the aluminum alloy may be greater than an etching selectivity ratio of the photoresist layer of the primary dry etching to the aluminum or the aluminum alloy.

[0028] According to exemplary embodiments, damage to an OLED display during a manufacturing process may be prevented, and high-resolution and high-speed driving of the OLED display may be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional view of an organic light emitting diode display according to an exemplary embodiment of the inventive concept.

[0030] Figure 2 is a flowchart of a method for manufacturing an organic light emitting diode display according to an exemplary embodiment.

[0031] Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 is a cross-sectional view of each process of a method of manufacturing an organic light emitting diode display according to an exemplary embodiment.

[0032] Figure 8 : is a graph showing an etching selectivity ratio of aluminum (Al) and a photoresist material PR according to a content of nitrogen (N).

[0033] Fig. 9 is a graph showing the etching ratio of each material according to the applied electric power.

[0034] Fig.10 is an image of a comparison example.

[0035] Fig.11 is an image of aluminum wiring after preliminary dry etching.

[0036] Fig.12 is an image of aluminum wiring after secondary dry etching.

[0037] Fig.13 is a cross-sectional view of an OLED display according to another exemplary embodiment. DETAILED DESCRIPTION

[0038] Hereinafter, the inventive concept will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the inventive concept are shown. As will be appreciated by those skilled in the art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the inventive concept.

[0039] The drawings and description are to be regarded as illustrative in nature and not restrictive. Throughout the specification, like reference numerals refer to like elements.

[0040] In addition, since the size and thickness of each element shown in the drawings are arbitrarily shown for the convenience of description, the inventive concept is not necessarily limited to the size and thickness of each element shown in the drawings. In the drawings, the thickness of layers, films, panels, regions, etc. are exaggerated for the sake of clarity. In addition, in the drawings, the thickness of some layers, films, panels, regions, etc. are exaggerated for the convenience of description.

[0041] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements. The terms "on" or "above" mean positioned on or below an object portion, and do not necessarily mean positioned on the upper side of an object portion based on the direction of gravity.

[0042] In addition, unless explicitly described to the contrary, the term “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0043] In addition, in this specification, the phrase "on a plane" means observing an object portion from the top, and the phrase "on a cross section" means observing a cross section formed by vertically cutting the object portion from the side.

[0044] Reference Figure 1 , an organic light emitting diode display according to an exemplary embodiment of the inventive concept will be described. Figure 1 is a cross-sectional view of an organic light emitting diode display according to an exemplary embodiment of the inventive concept.

[0045] Reference Figure 1 According to the present exemplary embodiment, the organic light emitting diode display includes a substrate 110. The substrate 110 may include a bendable, foldable, or rollable flexible material such as plastic, etc. For example, the substrate 110 may include polyimide (PI), polyethylene naphthalate (PEN), polycarbonate (PC), polyarylate (PAR), polyetherimide (PEI), polyethersulfone (PES), etc.

[0046] The buffer layer 120 is disposed on the substrate 110. The buffer layer 120 may include silicon nitride (SiN x ) and silicon oxide (SiO 2 The buffer layer 120 is disposed between the substrate 110 and the semiconductor layer 130 to be described later, and improves the quality of polycrystalline silicon by blocking impurities from the substrate 110 during a crystallization process for forming polycrystalline silicon, and releases stress of the semiconductor layer 130 formed on the buffer layer 120 by planarizing the substrate 110.

[0047] The semiconductor layers 130 are disposed on the buffer layer 120. Each of the semiconductor layers 130 may be formed of polysilicon or an oxide semiconductor.

[0048] The semiconductor layer 130 may be formed of polycrystalline silicon, and include a channel region 131, a source region 136, and a drain region 137. The source region 136 and the drain region 137 are respectively disposed on opposite sides of the channel region 131. The channel region 131 is an intrinsic semiconductor in which impurities are not doped, and the source region 136 and the drain region 137 are impurity semiconductors in which conductive impurities are doped. The semiconductor layer 130 may be formed of an oxide semiconductor, and in this case, an additional protective layer may be included to protect the oxide semiconductor material that is vulnerable to an external environment such as high temperature.

[0049] The gate insulating layer 140 is disposed on the semiconductor layer 130 to cover the semiconductor layer 130. The gate insulating layer 140 may include silicon nitride (SiN x ) and silicon oxide (SiO 2 ) is a single layer or multiple layers of at least one of ).

[0050] The gate electrode 155 is disposed on the gate insulating layer 140. Each gate electrode 155 is disposed to overlap the channel region 131 of the semiconductor layer 130. In a cross-sectional view, the gate electrode 155 may have a trapezoidal shape whose lower width is greater than the upper width. The bottom surface of each gate electrode 155 may match a region corresponding to the channel region 131 of each semiconductor layer 130.

[0051] The gate electrode 155 is formed of a single layer of aluminum (Al) or an aluminum alloy. Aluminum (Al) has a lower resistance (Ω) than molybdenum (Mo). In the organic light emitting diode (OLED) display according to the present exemplary embodiment, the gate electrode 155 includes a single layer of aluminum (Al) or an aluminum alloy, so even if the thickness of the gate electrode 155 is thin, the resistance is low enough to quickly transmit signals. When the thickness is the same, the signal transmission speed of the gate electrode including a single layer of aluminum (Al) or an aluminum alloy is higher than the signal transmission speed of the gate electrode including molybdenum (Mo), so the OLED display can be driven at high speed.

[0052] The gate electrode 155 may have a thickness less than When the thickness of the gate electrode 155 is or more When the gate electrode 155 is disposed, pressure is locally applied to a region where the gate electrode 155 is disposed, and thus a glass substrate attached for a post process may be damaged.

[0053] The taper angle of the gate electrode 155 is equal to 65° or less. The taper angle means an angle formed by the side surface of the gate electrode 155 and the gate insulating layer 140. When the taper angle of the gate electrode 155 exceeds 65°, the inorganic insulating layer formed over the gate electrode 155 may be disconnected, or the wiring formed over the gate electrode 155 and the gate electrode 155 may be short-circuited. However, in the organic light emitting diode display according to the present exemplary embodiment, the taper angle of the gate electrode 155 is equal to or less than 65°, and thus defects that may occur due to the taper angle of the gate electrode 155 can be prevented.

[0054] The organic light emitting diode display according to the present exemplary embodiment includes a gate wiring for transmitting a gate signal and a data wiring (not shown) for transmitting a data signal. Figure 1 In the embodiment of the present invention, the gate electrode 155 is shown as an example of the gate wiring, but this is not restrictive. The features of the gate electrode 155 described above can be applied to any portion of the gate wiring that transmits a gate signal.

[0055] The interlayer insulating layer 160 is disposed on the gate electrode 155 and the gate insulating layer 140. The interlayer insulating layer 160 may include silicon nitride (SiN x ) or silicon oxide (SiO 2). Openings that respectively expose the source region 136 and the drain region 137 of the semiconductor layer 130 are respectively provided in the gate insulating layer 140 and the interlayer insulating layer 160 .

[0056] The source electrode 165 and the drain electrode 166 are disposed on the interlayer insulating layer 160. The source electrode 165 and the drain electrode 166 are connected to the source region 136 and the drain region 137 of the semiconductor layer 130 through openings formed in the interlayer insulating layer 160 and the gate insulating layer 140, respectively.

[0057] The passivation layer 180 is disposed on the interlayer insulating layer 160, the source electrode 165, and the drain electrode 166. The passivation layer 180 flattens the steps formed by the interlayer insulating layer 160, the source electrode 165, and the drain electrode 166 by covering the interlayer insulating layer 160, the source electrode 165, and the drain electrode 166, so that the pixel electrode 191 can be formed on the passivation layer 180 without a step difference. The passivation layer 180 may be formed of an organic material such as a polyacrylate resin, a polyimide resin, or a stacked layer of an organic material and an inorganic material.

[0058] The pixel electrode 191 is disposed on the passivation layer 180. The pixel electrode 191 is connected to the drain electrode 166 through an opening formed in the passivation layer 180.

[0059] The driving transistor formed by the gate electrode 155, the semiconductor layer 130, the source electrode 165 and the drain electrode 166 is connected to the pixel electrode 191 and supplies a driving current to the organic light emitting diode OLED. The organic light emitting diode display according to the present exemplary embodiment may further include: a switching transistor (not shown) connected to the data line and transmitting a data voltage in response to a scan signal; and a compensation transistor (not shown) connected to the driving transistor and compensating for a threshold voltage of the driving transistor in response to the scan signal.

[0060] The partition wall 350 is disposed on the passivation layer 180 and the pixel electrode 191 to cover the passivation layer 180 and the pixel electrode 191, and includes a pixel opening 351 exposing the pixel electrode 191. The partition wall 350 may include an organic material such as polyacrylate resin, polyimide resin, etc., or a silicon dioxide-based inorganic material.

[0061] The organic emission layer 370 is disposed on a portion of the pixel electrode 191 exposed by the pixel opening 351. The organic emission layer 370 may be formed of a low molecular weight organic material or a high molecular weight organic material such as PEDOT (poly (3,4-ethylenedioxythiophene)). In addition, the organic emission layer 370 may be a multilayer including at least one of a functional layer such as a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL).

[0062] The organic emission layer 370 may include a red organic emission layer, a green organic emission layer, and a blue organic emission layer, which emit red light, green light, and blue light, respectively, so that a color image can be realized.

[0063] The common electrode 270 is disposed on the organic emission layer 370. The common electrode 270 may be disposed over a plurality of pixels. The pixel electrode 191, the organic emission layer 370, and the common electrode 270 may form an organic light emitting diode OLED.

[0064] Here, the pixel electrode 191 may be an anode as a hole injection electrode, and the common electrode 270 may be a cathode as an electron injection electrode. However, the present exemplary embodiment is not limited thereto, and according to a driving method of the organic light emitting diode display, the pixel electrode 191 may be a cathode, and the common electrode 270 may be an anode. Holes and electrons are injected from the pixel electrode 191 and the common electrode 270 into the organic emission layer 370, respectively, and excitons generated by combining the injected holes and electrons transition from an excited state to a ground state to emit light.

[0065] An encapsulation layer (not shown) may be further provided on the common electrode 270. The encapsulation layer may include a plurality of layers and may be formed as a composite layer including both an inorganic layer and an organic layer, or may be formed as three layers in which an inorganic layer, an organic layer, and an inorganic layer are sequentially stacked.

[0066] In the following, reference will be made to Figures 2 to 7 A method for manufacturing an organic light emitting diode display according to an exemplary embodiment is described. Figure 2 is a flowchart of a method for manufacturing an organic light emitting diode display according to an exemplary embodiment.

[0067] Reference Figure 2, a method for manufacturing an organic light emitting diode display according to an exemplary embodiment includes sequentially forming a conductive layer and a photoresist layer on a gate insulating layer (S101). The conductive layer is formed as a single layer of aluminum (Al) or an aluminum alloy. Next, the photoresist layer is exposed and developed by using a photomask to form a photoresist pattern (S102). The photoresist layer can be formed as a positive photoresist or a negative photoresist. Next, a primary dry etching is performed by using a mixed gas containing 10% to 50% nitrogen (N) (S103). After performing the primary dry etching, a secondary dry etching is performed by using a mixed gas containing 80% to 90% nitrogen (N) and applying a predetermined electric power (S104). Through two dry etching processes, a gate wiring pattern is formed. After the gate wiring pattern is formed, the residual photoresist pattern is removed (S105), and subsequent processes are performed to complete the organic light emitting diode display.

[0068] Figures 3 to 7 is a cross-sectional view of each process of a method for manufacturing an organic light emitting diode display according to an exemplary embodiment. Figure 1 Description of constituent elements that are the same as those in FIG.

[0069] Reference Figure 3 , a conductive layer 155-1 and a photoresist layer PRL such as a positive photoresist layer are sequentially formed on the gate insulating layer 140. The conductive layer 155-1 includes a single layer of aluminum (Al) or an aluminum alloy. When aluminum (Al) is included, the resistance is low compared to the case where molybdenum (Mo) is included therein. Therefore, the wiring formed of aluminum (Al) has a signal transmission speed faster than the signal transmission speed of the wiring formed of molybdenum (Mo) having the same thickness, and therefore, the organic light emitting diode display can be driven at high speed.

[0070] A photo mask PM having a transmission portion T and a light blocking portion B is disposed on the photoresist layer PRL, and light is applied to the photo mask PM to expose and develop the photoresist layer PRL.

[0071] When the photoresist layer PRL is a positive photoresist, the exposed portion of the photoresist layer PRL is removed. In this case, the photomask PM has a blocking portion B in a portion corresponding to a portion where a gate wiring is to be formed. On the other hand, when the photoresist layer PRL is provided as a negative photoresist, the exposed portion of the photoresist layer PRL remains. In this case, the photomask PM includes a transmissive portion T in a portion corresponding to a portion where a gate wiring is to be formed.

[0072] Reference Figure 4 , exposure and development Figure 3The photoresist layer PRL is formed by etching the photoresist pattern PRP. The region in which the photoresist pattern PRP is provided is a region corresponding to a portion in which a gate wiring is formed. The width W of the photoresist pattern initially formed before performing the etching process may be the same as the width of the portion in which the gate wiring is formed.

[0073] Reference Figure 5 ,right Figure 4 The conductive layer 155-1 is subjected to preliminary dry etching to form a preliminary gate pattern 155-2. In the preliminary dry etching process, a catalyst containing boron trichloride (BCl 3 ), chlorine (Cl 2 ) and nitrogen (N). In the preliminary dry etching process, argon (Ar) can be used instead of boron trichloride (BCl 3 ).

[0074] The amount of nitrogen (N) in the mixed gas may be from about 10% to about 50%. The preliminary dry etching may be performed at a pressure of about 10 mTorr to 30 mTorr. Through the preliminary dry etching, a polymer layer including nitrogen (N) of the mixed gas and carbon (C) of the photoresist pattern PRP is formed at the side surface of the conductive layer 155-1. Since the side surface of the conductive layer 155-1 is protected by the polymer layer, undercut does not occur in the preliminary gate pattern 155-2 including aluminum (Al) or aluminum alloy.

[0075] The width of the bottom side of the preliminary gate pattern 155-2 formed by the preliminary dry etching is greater than the width W of the preliminary photoresist pattern before the preliminary dry etching. The surface of the photoresist pattern PRP is also partially etched by the preliminary dry etching. Therefore, after the preliminary dry etching, the width of the photoresist pattern PRP becomes smaller than the width W of the initial photoresist pattern.

[0076] The shape of the cross section of the preliminary gate pattern 155-2 may be a trapezoid whose lower width is greater than the upper width. When a mixed gas with a nitrogen (N) content of 10% to 50% is preliminarily used for dry etching, the etching ratio of aluminum (Al) is greater than the etching ratio of the photoresist material. That is, the etching rate of the conductive layer 155-1 including aluminum (Al) is higher than the retraction speed of the photoresist pattern PRP. In this case, the retraction speed represents the etching speed of the photoresist pattern PRP.

[0077] As a result, a taper angle A1 formed by the side surface of the preliminary gate pattern 155 - 2 and the gate insulating layer 140 exceeds 65°, and thus the side surface of the preliminary gate pattern 155 - 2 becomes steep.

[0078] In the preliminary dry etching process, a process containing boron trichloride (BCl 3 ) and a dry etching process using a gas containing chlorine (Cl 2 ) and nitrogen (N) in a mixed gas. In other words, the preliminary dry etching process may use a mixed gas containing chlorine (Cl 2 ) and nitrogen (N), and can be performed using a mixed gas containing boron trichloride (BCl 3 ) gas. In addition, in the tertiary dry etching process, argon (Ar) can be used instead of boron trichloride (BCl 3 ).

[0079] Reference Figure 6 , through Figure 5 The secondary gate pattern 155-2 is subjected to secondary dry etching to form a secondary gate pattern 155-3. The secondary dry etching may be performed by reactive ion etching (RIE). The mixed gas used in the secondary dry etching includes boron trichloride (BCl 3 ), chlorine (Cl 2 ) and nitrogen (N). The content ratio of nitrogen (N) in the mixed gas can be from about 80% to about 90%. When performing the secondary dry etching, a predetermined electric power can be applied. For example, an electric power of 500W to 2000W can be applied. However, the intensity of the electric power is not limited thereto, and may be less than 500W or more than 2000W depending on the size of the object to be etched. In addition, the secondary dry etching can be performed at a pressure of about 10 mTorr to 30 mTorr.

[0080] The shape of the cross section of the secondary gate pattern 155-3 may be a trapezoid whose lower width is greater than the upper width. When the secondary dry etching is performed by using a mixed gas having a nitrogen content of 80% to 90% and by applying a predetermined electric power, the etching ratio of the photoresist material is greater than the etching ratio of aluminum (Al). That is, the retraction speed of the photoresist pattern PRP is higher than the etching rate of the preliminary gate pattern 155-2 containing aluminum (Al). As a result, the taper angle A2 formed by the side surface of the secondary gate pattern 155-3 and the gate insulating layer 140 is less than 65°, so the side surface of the secondary gate pattern 155-3 becomes less steep. Since the taper angle of the gate wiring does not exceed 65°, defects that may occur due to disconnection or short circuit of the stacked inorganic layers or wiring in the subsequent process can be prevented.

[0081] The width of the bottom side of the secondary gate pattern 155-3 formed by the secondary dry etching may be equal to the width W of the initial photoresist pattern. The surface of the photoresist pattern PRP is also partially etched by the secondary dry etching. Therefore, the width of the photoresist pattern PRP after the secondary dry etching becomes smaller than the width of the photoresist pattern PRP after the preliminary dry etching.

[0082] Reference Figure 7 , the remaining photoresist pattern PRP and the polymer layer formed at the side surface of the secondary gate pattern 155-3 can be removed by ashing. However, this is not restrictive, and any method that can remove the photoresist pattern PRP can be applied. Therefore, a gate wiring 155-4 having a taper angle of 65° or less is formed.

[0083] Figure 8 : is a graph showing the etching selectivity ratio of aluminum (Al) and photoresist material PR according to the content of nitrogen (N). The content of nitrogen (N) means the content ratio of nitrogen (N) in the mixed gas.

[0084] Reference Figure 8 It can be observed that as the content of nitrogen (N) in the mixed gas increases, the PR / Al etching selectivity ratio of the photoresist material PR to aluminum (Al) increases. Therefore, in the secondary dry etching process in which the content of nitrogen (N) is 80% to 90%, the photoresist pattern is etched faster than the gate pattern containing aluminum (Al). Therefore, a small taper angle may be formed.

[0085] In the case where the gate wiring of the organic light emitting diode display includes molybdenum (Mo), the etching process may be performed by using a molybdenum-containing oxide (O 2 ) mixed gas to adjust the etching selectivity ratio of the photoresist material and molybdenum (Mo). However, when the gate wiring includes aluminum (Al), aluminum (Al) and oxygen (O 2 ) reaction, thus producing AlO x particles, therefore, cannot use oxygen (O 2 According to an exemplary embodiment of the present inventive concept, nitrogen (N 2 ) is used as an ambient gas for etching to adjust the etching selectivity ratio of the photoresist material and aluminum (Al).

[0086] Fig. 9 is a graph showing the etching ratio of each material according to the applied electric power (bias power). Specifically, Fig. 9 The results show that when the nitrogen (N) content in the mixed gas is 85%, the photoresist material PR, aluminum (Al), silicon nitride (SiN x ) and silicon oxide (SiO 2) and the PR / Al etching selectivity ratio of the photoresist material PR to aluminum (Al).

[0087] Reference Fig. 9 As the applied power increases, the etching rate of the photoresist material PR and the etching selectivity of the photoresist material PR to aluminum (Al) increase. Therefore, in the secondary dry etching performed with a nitrogen (N) content of 80% to 90% and a predetermined electric power applied thereto, the etching of the photoresist pattern PRP occurs faster than the preliminary gate pattern 155-2 including aluminum (Al). When the photoresist pattern PRP retracts quickly, the upper surface of the edge of the gate wiring can be exposed to the mixed gas, and the side surface of the gate wiring can be formed more smoothly, so that the taper angle formed by the side surface of the gate wiring and the gate insulating layer can be formed small. In addition, the desired taper angle of the gate wiring can be achieved by adjusting the applied electric power.

[0088] Fig.10 is an image of a comparison example. Fig.10 It is shown that by using boron trichloride (BCl 3 ) and chlorine (Cl 2 ) mixed gas to perform dry etching on silicon oxide (SiO 2 ) is a cross-section of an aluminum wiring formed on a substrate. Fig.10 When dry etching is performed using a mixed gas that does not contain nitrogen (N), the bottom of the aluminum wiring is over-etched, resulting in undercutting.

[0089] Fig.11 is an image of the aluminum wiring after preliminary dry etching. Fig.11 In the process, by using a mixture containing boron trichloride (BCl 3 ), chlorine (Cl 2 ) and a mixed gas of nitrogen (N) with a content of 10% to 50% to perform dry etching on silicon oxide (SiO 2 ) is formed on the aluminum wiring. In this case, Fig.10 Unlike the comparative example of , undercutting does not occur at the bottom of the aluminum wiring. This is because a polymer layer including nitrogen (N) in a mixed gas and carbon (C) having a photoresist pattern is formed at the side surface of the aluminum wiring, thereby protecting the side surface of the aluminum wiring.

[0090] Reference Fig.11 , the taper angle of the aluminum wiring is as steep as 72.7°. This is because, as described above, when dry etching is performed using a mixed gas having a nitrogen content of 10% to 50%, the etching rate of aluminum (Al) is greater than the etching rate of the photoresist material.

[0091] Fig.12is an image of the aluminum wiring after secondary dry etching. Fig.12 In the process, by using a mixture containing boron trichloride (BCl 3 ), chlorine (Cl 2 ) and nitrogen (N) at a content of 80% to 90% and applying an electric power of 500W to 2000W to perform dry etching, 2 ) is formed on an aluminum wiring.

[0092] exist Fig.12 In the example, the cone angle of the aluminum wiring is 57°. Fig.11 Compared with the comparative example of , the taper angle of the aluminum wiring is formed to be as small as less than 65°. This is because when dry etching is performed by using a mixed gas having a nitrogen content of 80% to 90% and applying a predetermined electric power, the etching rate of aluminum (Al) is smaller than the etching rate of the photoresist material.

[0093] Fig.13 is a cross-sectional view of an OLED display according to another exemplary embodiment. Figure 1 Description of the same constituent elements as those in Figure 1 Different from OLED displays, Fig.13 The OLED display further includes a gate capping layer 156 on the gate electrode 155 .

[0094] The gate electrode 155 includes aluminum (Al) or an aluminum alloy. The gate cap layer 156 includes titanium (Ti) or titanium nitride (TiN x ). The gate capping layer 156 may prevent the gate electrode 155 formed of aluminum (Al) from being damaged by a buffered oxide etching (BOE) solution used in a subsequent process.

[0095] Although the gate capping layer 156 is described as being disposed on the gate electrode 155, it is not limited thereto. Fig.13 , the gate capping layer 156 may be disposed under the gate electrode 155 , or the gate capping layer 156 may be disposed on the gate electrode 155 and disposed under the gate electrode 155 .

[0096] The gate electrode 155 and the gate capping layer 156 of the OLED display according to the present exemplary embodiment may be formed by sequentially stacking a single layer of aluminum (Al) or an aluminum alloy and a single layer of a material including titanium (Ti) or titanium nitride (TiN). x ) layer; perform preliminary dry etching on the two layers together; and then perform secondary dry etching on the two layers after the preliminary dry etching. Therefore, the gate electrode 155 and the gate cap layer 156 overlap each other, and the edge of the upper surface of the gate electrode 155 and the edge of the bottom surface of the gate cap layer 156 can match.

[0097] While the inventive concept has been described in conjunction with what are presently considered to be practical exemplary embodiments, it is to be understood that the inventive concept is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the present disclosure.

Claims

1. A method for manufacturing an organic light emitting diode display, wherein: The method for manufacturing an organic light emitting diode display comprises: forming a gate insulating layer on the substrate; and forming a gate wiring on the gate insulating layer, Wherein, forming the gate wiring comprises: sequentially forming a conductive layer including aluminum or an aluminum alloy and a photoresist layer; etching the conductive layer by preliminary dry etching to form a preliminary gate pattern; and etching the preliminary gate pattern by secondary dry etching to form a secondary gate pattern, The primary dry etching and the secondary dry etching use a mixed gas containing chlorine and nitrogen. In the preliminary dry etching, the content of nitrogen in the mixed gas is from 10% to 50%, and in the secondary dry etching, the content of nitrogen in the mixed gas is from 80% to 90%.

2. The method for manufacturing an organic light emitting diode display according to claim 1, wherein: The mixed gas further comprises boron trichloride or argon.

3. The method for manufacturing an organic light emitting diode display according to claim 2, wherein: The taper angle of the preliminary gate pattern exceeds 65°, and The taper angle of the secondary gate pattern is less than 65°.

4. The method for manufacturing an organic light emitting diode display according to claim 3, wherein: The method for manufacturing an organic light emitting diode display further includes forming a gate capping layer on the gate wiring, Wherein, the gate cap layer comprises titanium or titanium nitride.

5. The method for manufacturing an organic light emitting diode display according to claim 1, wherein: An etching selectivity ratio of the photoresist layer to the aluminum or the aluminum alloy in the secondary dry etching is greater than an etching selectivity ratio of the photoresist layer to the aluminum or the aluminum alloy in the preliminary dry etching.

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