KR100835919B1 - Electroluminescent element and manufacturing method thereof - Google Patents

Abstract

The present invention provides a substrate, an insulating film including a first electrode positioned on the substrate, an opening positioned on the first electrode and exposing a portion of the first electrode, a light emitting layer located in the opening, and a second electrode positioned on the light emitting layer. And an auxiliary electrode positioned in an arbitrary region of the lower or upper portion except for the opening of the insulating layer and electrically connected to the second electrode, wherein the auxiliary electrode includes a metal film made of chromium or chromium oxide, and a method of manufacturing the same. To provide.

Electroluminescent element, second electrode, auxiliary electrode

Description

Electroluminescent device and method of manufacturing the same {Light emitting device and fabrication method of the same}

1 is a cross-sectional view of an electroluminescent device according to the prior art.

2 is a cross-sectional view of an electroluminescent device according to an embodiment of the present invention.

3A to 7B are plan views and cross-sectional views for each process for describing a method of manufacturing an electroluminescent device according to an embodiment of the present invention.

8 is a cross-sectional view and a plan view showing an electroluminescent device according to another embodiment of the present invention.

9A to 11B are cross-sectional views of processes for describing a method of manufacturing an electroluminescent device according to another exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

200: substrate 205: semiconductor layer

210: first insulating film 215: gate electrode

220: second insulating films 225a and 225b: source electrode and drain electrode

T: thin film transistor 230: third insulating film

240: first electrode 250: fourth insulating film

255: opening 260: auxiliary electrode

270: light emitting layer 280: second electrode

The present invention relates to an electroluminescent device and a method of manufacturing the same.

Among flat panel display devices, a light emitting device is a self-luminous display device that electrically excites a compound to emit light. The electroluminescent device does not require a backlight used in the liquid crystal display device, so it is not only light in weight but also simplifies the process. In addition, low-temperature fabrication is possible, response speed is 1ms or less, high speed response speed, low power consumption, wide viewing angle, high contrast and the like.

Among them, the organic light emitting device includes a light emitting layer made of an organic material between the anode and the cathode so that holes supplied from the anode and electrons supplied from the cathode combine in the organic light emitting layer to form an exciton, a hole-electron pair. The excitons again emit light due to the energy generated as they return to the ground state.

In order to implement full color, the organic light emitting diode as described above should include a plurality of pixels including red, green, and blue light emitting layers, and the red, green, and blue light emitting layers may be respectively patterned by vacuum deposition.

1 is a cross-sectional view showing the structure of an electroluminescent device according to the prior art.

Referring to FIG. 1, on the substrate 100, a semiconductor layer 105, a first insulating film 110 as a gate insulating film, a gate electrode 115, a second insulating film 120 as an interlayer insulating film, a source electrode and a drain The thin film transistor T including the electrodes 125a and 125b is positioned.

The third insulating layer 130 may be positioned on the thin film transistor T for planarization or passivation, and the first electrode 140, the emission layer 170, and the second electrode 180 may be disposed on the third insulating layer 130. It includes a light emitting diode.

The first electrode 140 is formed to be divided for each pixel, and is electrically connected to the drain electrode 125b through the third insulating layer 130. The fourth insulating layer 150 including an opening 155 may be disposed on the first electrode 140 to insulate the first electrodes and expose a portion of the first electrode 140, and the light emitting layer 170 may be disposed on the first electrode 140. It is located in the opening 155. The emission layer 170 may include red, green, and blue, and may be patterned for each pixel by performing a vacuum deposition method using a shadow mask. The second electrode 180 is positioned on the substrate 100 including the emission layer 140 and is formed as a front electrode.

The EL device may be classified into a bottom emission type, a top emission type, or a double emission type according to a direction in which light generated from the light emitting diode is extracted. In this case, since the front emission type electroluminescent device emits light in a direction opposite to the substrate, the second electrode may be formed of a transparent conductive film such as indium tin oxide (ITO) or metal to transmit light. It is formed to a thin thickness.

However, when the second electrode is formed as described above, there is a problem in that the sheet resistance of the second electrode is increased. In addition, since the second electrode is formed in the form of a front electrode, signals transmitted to each pixel are delayed by the sheet resistance of the second electrode, resulting in uneven luminance of each pixel. In particular, in the case of a large area electroluminescent device, the delay of such signal transmission is more serious, and thus there is a problem that a desired image image cannot be represented.

Accordingly, an object of the present invention is to provide an electroluminescent device and a method of manufacturing the same, which can improve the uniformity of luminance and the quality of the screen.

In order to achieve the above object, the present invention, an insulating film comprising a substrate, a first electrode located on the substrate, an opening positioned on the first electrode and exposing a portion of the first electrode, a light emitting layer located in the opening, the light emitting layer The present invention provides an electroluminescent device comprising a second electrode positioned above and an auxiliary electrode positioned below or above the insulating layer and electrically connected to the second electrode.

The present invention also provides a substrate, forming a first electrode on the substrate, forming an insulating film including an opening that exposes the first electrode on the first electrode, on the insulating film except the opening Forming an auxiliary electrode, forming a light emitting layer to expose at least a part of the auxiliary electrode on the insulating film including the opening, and forming a second electrode on the substrate including the light emitting layer and the auxiliary electrode. It provides a manufacturing method.

In addition, the present invention provides a method of forming a substrate comprising: providing a substrate, forming an auxiliary electrode between the first electrodes to be spaced apart from the first electrode and the first electrode on the substrate, and forming the first electrode on the first electrode and the auxiliary electrode. Forming an insulating layer including an opening exposing the opening and a via hole exposing the auxiliary electrode, forming a light emitting layer to expose at least a portion of the via hole on the insulating film including the opening, and electrically connecting the auxiliary electrode through the via hole It provides a method of manufacturing an electroluminescent device comprising forming a second electrode on a substrate including a light emitting layer.

Hereinafter, with reference to the accompanying drawings, it will be described embodiments of the present invention;

2 is a cross-sectional view showing the structure of an electroluminescent device according to an embodiment of the present invention.

2, a semiconductor layer 205, a first insulating film 210, a gate electrode 215, a second insulating film 220, a source electrode and a drain electrode 225a and 225b are included on a substrate 200. The thin film transistor T is positioned.

The third insulating layer 230 is positioned on the source and drain electrodes 225a and 225b. The third insulating film 230 may be an insulating film for planarization or passivation, and the first electrode 240 may be electrically connected to the drain electrode 225b through the third insulating film 230 on the third insulating film 230. This is located.

The fourth insulating layer 250 is positioned on the first electrode 240. The fourth insulating layer 250 is a pixel definition layer and includes an opening 255 that insulates the first electrodes 240 and exposes a portion of the first electrode 240.

The auxiliary electrode 260 is positioned on the fourth insulating layer 250 except for the opening 255. The auxiliary electrode 260 may be formed of one or more metal films having low resistance, and include chromium (Cr), aluminum (Al), molybdenum (Mo), copper (Cu), tungsten (W), silver (Ag), and nickel ( Ni), gold (Au) and alloys thereof may be any one or more selected from the group consisting of. In particular, the film of any one of the auxiliary electrodes 260 may be made of chromium (Cr). In addition, the auxiliary electrode 260 may further include a metal oxide layer. Here, the metal oxide film may include chromium oxide (CrOx), and when the auxiliary electrode 260 includes a metal oxide film, the uppermost film should be a metal film.

The emission layer 270 is positioned in the opening 255. The light emitting layer 270 may be formed of an organic material. In this case, the emission layer 270 is positioned to expose at least a portion of the auxiliary electrode 260.

The second electrode 280 is positioned on the substrate 200 including the emission layer 270 and the auxiliary electrode 260. The second electrode 280 may be an anode, and is formed as a front electrode to be electrically connected to the light emitting layer 270 and the auxiliary electrode 260 formed in all pixels.

Hereinafter, a method of manufacturing an electroluminescent device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

3A to 6B are plan and cross-sectional views of processes for describing a method of manufacturing an electroluminescent device according to an embodiment of the present invention. Here, the cross-sectional views show the cross sections cut along the line II ′ of the plan views.

3A and 3B, a semiconductor layer 305 made of amorphous silicon or polycrystalline silicon is formed on the substrate 300. After forming the first insulating film 310, which is a gate insulating film, on the substrate 300 including the semiconductor layer 305, the gate electrode 315 is formed on the first insulating film 310 to correspond to a predetermined region of the semiconductor layer 305. ). The gate electrode 315 may be formed using aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), molybdenum alloy (Mo alloy), tungsten (W) or tungsten silicide (WSi ₂ ).

After forming the second insulating film 320, which is an interlayer insulating film, on the gate electrode 315, the second insulating film 320 is electrically connected to the semiconductor layer 305 through the first and second insulating films 310 and 320. Source and drain electrodes 325a and 325b are formed. The source and drain electrodes 325a and 325b may be formed of a low resistance material, for example, molybdenum tungsten (MoW), titanium (Ti), aluminum (Al), or an aluminum alloy (Al alloy) to lower wiring resistance. have. As a result, the thin film transistor T including the semiconductor layer 305, the first insulating layer 310, the gate electrode 315, the second insulating layer 320, the source electrode, and the drain electrodes 325a and 325b is formed.

4A and 4B, a third insulating layer 330 is formed on the source and drain electrodes 325a and 325b. The third insulating film 330 may be an insulating film for planarization or passivation, and the third insulating film 330 may be formed using polyimide resin, polyacrylic resin, benzo cyclobutene resin, silicon nitride, or silicon oxide. Can be.

A first electrode 340 is formed on the third insulating layer 330 to be electrically connected to the drain electrode 325b through the third insulating layer 330. Here, the first electrode 340 may be a cathode, and the first electrode 340 is made of magnesium (Mg), silver (Ag), aluminum (Al), chromium (Cr), calcium (Ca), or an alloy thereof. Can be done.

Referring to FIGS. 5A and 5B, a fourth insulating layer 350, which is a pixel defining layer that insulates the first electrodes 340, is formed on the first electrode 340. Then, the fourth insulating film 350 is etched by performing a photolithography process to form an opening 355 exposing a part of the first electrode 340 in the fourth insulating film 350.

The auxiliary electrode 360 is formed on the fourth insulating layer 350. The auxiliary electrode 360 may be formed by stacking the auxiliary electrode metal film on the fourth insulating film 350 and patterning the auxiliary electrode metal film using a photolithography process.

Here, the auxiliary electrode 360 may be formed of one or more metal films using a metal having low resistance, and include chromium (Cr), aluminum (Al), molybdenum (Mo), copper (Cu), tungsten (W), It may be formed of any one or more selected from the group consisting of silver (Ag), nickel (Ni), gold (Au) and alloys thereof.

In particular, the metal film of any one of the auxiliary electrodes 360 may be made of chromium (Cr). In this case, when the auxiliary electrode 360 includes a film made of chromium (Cr), the auxiliary electrode 360 may simultaneously serve as a black matrix, thereby increasing the contrast ratio of the electroluminescent device. .

In addition, the auxiliary electrode 360 may be formed to further include a metal oxide layer. Here, the metal oxide film may include chromium oxide (CrOx). When the auxiliary electrode 360 includes chromium oxide, the metal oxide layer may function as a black matrix. In this case, in order to serve as the auxiliary electrode 360, the uppermost layer of the auxiliary electrode 360 is a metal film, and a metal oxide film should be included below.

In one embodiment of the present invention, the opening 355 and the auxiliary electrode 360 exposing a part of the first electrode 340 are sequentially formed. However, a metal film for the auxiliary electrode is formed on the fourth insulating film 350. After lamination, the opening 355 and the auxiliary electrode 360 may be simultaneously formed by using a halftone mask process.

6A and 6B, the light emitting layer 370 is formed in the opening 355. The emission layer 370 may be formed of an organic material, and although not shown, an electron injection layer and / or an electron transport layer may be further formed between the emission layer 370 and the first electrode 340. In addition, a hole transport layer and / or a hole injection layer may be further formed on the emission layer 370.

The emission layer 370 may include red, green, and blue emission layers. The emission layer 370 may be formed by performing a vacuum deposition method using the shadow mask 375. The shadow mask includes an opening 375a and a blocking part 375b, so that the organic material may be deposited only on a desired area. In this case, the emission layer 370 should be formed to expose a part of the auxiliary electrode 360 so that the second electrode and the auxiliary electrode 360 to be subsequently formed are electrically connected. Therefore, the shadow mask should include the blocking portion 375b in an area corresponding to at least a part of the auxiliary electrode 360 when the shadow mask is aligned with the substrate 300.

7A and 7B, a second electrode 380 is formed on a substrate including the light emitting layer 370 and the auxiliary electrode 360. The second electrode 380 may be an anode, and may be formed of a transparent conductive film having a high work function such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). Can be. Unlike this, the second electrode 380 may be formed using a thin magnesium (Mg), silver (Ag), aluminum (Al), or the like, and may further include a transparent conductive film to match the work function. have. The second electrode 380 is not patterned for each pixel, but is formed as a front electrode on the substrate 300.

In one embodiment of the present invention, the second electrode 380 is electrically connected to the auxiliary electrode 360 positioned on the fourth insulating film 350. Since the auxiliary electrode 360 is formed of a metal material having a low resistance, the auxiliary electrode 360 serves to lower the sheet resistance of the second electrode 380 made of a transparent conductive film or a thin conductive film. Therefore, when driving the electroluminescent device, the signal delay due to the sheet resistance of the second electrode 380 can be prevented to make the luminance of each pixel uniform.

In addition, when the auxiliary electrode 360 is formed of a multi-layered film including chromium or chromium oxide, the auxiliary electrode 360 may simultaneously perform a role of a black matrix, which may improve the visibility of the electroluminescent device. have.

In addition, since the auxiliary electrode 360 according to the exemplary embodiment is patterned at the same time when the opening of the fourth insulating layer is formed, there is an advantage that the process is simple and does not use an additional mask.

8 is a cross-sectional view showing the structure of an electroluminescent device according to another embodiment of the present invention.

Referring to FIG. 8, a semiconductor layer 405, a first insulating layer 410, a gate electrode 415, a second insulating layer 420, a source electrode, and a drain electrode 425a and 425b are included on a substrate 400. The thin film transistor T is positioned.

The third insulating layer 430 is positioned on the source and drain electrodes 425a and 425b. The third insulating film 430 may be an insulating film for planarization or passivation, and the first electrode 440 is electrically connected to the drain electrode 425b through the third insulating film 430 on the third insulating film 430. This is located.

The first electrode 440 may be patterned for each pixel, and the auxiliary electrode 460 is positioned between the first electrodes 440. Here, the first electrode 440 and the auxiliary electrode 460 may be formed on the same plane by stacking a predetermined metal film and then patterning it. However, since the auxiliary electrode 460 is electrically connected to the second electrode to be subsequently formed, the first electrode 440 and the auxiliary electrode 460 are spaced apart from each other to prevent a short circuit between the first and second electrodes. Located.

The auxiliary electrode 460 may be formed of one or more metal films having low resistance, and include chromium (Cr), aluminum (Al), molybdenum (Mo), copper (Cu), tungsten (W), silver (Ag), and nickel ( Ni), gold (Au) and alloys thereof may be any one or more selected from the group consisting of. In particular, any one film of the auxiliary electrode 460 may be made of chromium (Cr). In addition, the auxiliary electrode 460 may further include a metal oxide layer. Here, the metal oxide film may include chromium oxide (CrOx), and when the auxiliary electrode 460 includes the metal oxide film, the uppermost film should be a metal film.

The fourth insulating layer 450 is positioned on the first electrode 440 and the auxiliary electrode 460. The fourth insulating layer 450 is a pixel definition layer, which insulates the first electrodes 440 from each other, exposes an opening 455 that exposes a portion of the first electrode 440, and a via hole 457 that exposes a portion of the auxiliary electrode. It includes.

The emission layer 470 is positioned in the opening 455. The emission layer 470 may be formed of an organic material, and may include red, green, and blue emission layers.

The second electrode 480 is positioned on the auxiliary electrode 460 exposed by the light emitting layer 470 and the via hole 457. Here, the second electrode 480 may be an anode, and the second electrode 480 is formed as a front electrode to be electrically connected to the light emitting layer 470 and the auxiliary electrode 460 positioned in all pixels.

Hereinafter, a method of manufacturing an electroluminescent device according to another embodiment of the present invention will be described with reference to the accompanying drawings.

9A to 11B are plan views and cross-sectional views for each process for describing a method of manufacturing an electroluminescent device according to another exemplary embodiment of the present invention. Here, the cross-sectional views show cross sections taken along the line II-II 'of the plan views.

9A and 9B, the semiconductor layer 505, the first insulating layer 510, the gate electrode 515, the second insulating layer 520, the source electrode and the drain electrode 525a and 525b are disposed on the substrate 500. To form a thin film transistor (T) comprising a.

Then, a third insulating film 530 is formed on the source and drain electrodes 525a and 525b.

The first electrode 540 and the first electrode 540 that are electrically connected to the drain electrode 525b through the third insulating layer 530 and are then etched by stacking a metal film on the third insulating layer 530. The auxiliary electrodes 560 positioned between the first electrodes 540 and spaced apart from each other are simultaneously formed. Therefore, the auxiliary electrode 560 may be formed in a lattice structure as shown in FIG. 9A.

Here, the first electrode 540 may be a cathode, and the first electrode 540 may be aluminum (Al), molybdenum (Mo), copper (Cu), tungsten (W), silver (Ag), or nickel (Ni). It may be formed of any one or more selected from the group consisting of gold (Au), chromium (Cr), calcium (Ca) and alloys thereof. The auxiliary electrode 560 may be formed of the same material as the first electrode 540. Alternatively, the auxiliary electrode 560 may include an additional metal film in addition to the metal film made of the same material as the first electrode 540. Can be.

In particular, the metal film of any one of the auxiliary electrodes 560 may be made of chromium (Cr). Here, when the auxiliary electrode 560 includes a film made of chromium (Cr), the auxiliary electrode 560 may simultaneously perform a role of a black matrix, thereby increasing the contrast ratio of the electroluminescent device.

In addition, the auxiliary electrode 560 may be formed to further include a metal oxide layer. Here, the metal oxide film may include chromium oxide (CrOx). When the auxiliary electrode 560 includes chromium oxide, the metal oxide layer may function as a black matrix. At this time, in order to serve as the auxiliary electrode 560, the uppermost layer of the auxiliary electrode 560 should be a metal film, and a metal oxide film should be included below.

As such, when the auxiliary electrode 560 is formed to have a multi-layered structure, the first electrode 540 and the auxiliary electrode 560 may be simultaneously formed by performing a halftone mask process.

10A and 10B, a fourth insulating layer 550 is formed on the first electrode 540 and the auxiliary electrode 560 to form a pixel defining layer that insulates the first electrodes 540 from each other. Then, the fourth insulating layer 550 is etched by performing a photolithography process, and a portion of the opening 555 and the auxiliary electrode 560 exposing a part of the first electrode 540 is exposed in the fourth insulating layer 550. A via hole 557 for exposing is formed.

Subsequently, the light emitting layer 570 is formed in the opening 555. The emission layer 570 may be formed of an organic material, and although not shown, an electron injection layer and / or an electron transport layer may be further formed between the emission layer 570 and the first electrode 540. In addition, a hole transport layer and / or a hole injection layer may be further formed on the emission layer 570.

The light emitting layer 570 may include red, green, and blue light emitting layers. The emission layer 570 may be formed by performing a vacuum deposition method using the shadow mask 575. The shadow mask 575 includes an opening 575a and a blocking portion 575b, so that the organic material may be deposited only on a desired area. The light emitting layer 570 should be formed to expose a part of the auxiliary electrode 560 so that the second electrode and the auxiliary electrode 560 to be subsequently formed are electrically connected. Therefore, the shadow mask 575 used at this time should include a blocking portion 575b in an area corresponding to the via hole 557 exposing at least a part of the auxiliary electrode 560 when the substrate 500 is aligned with the substrate 500.

11A and 11B, a second electrode 580 is formed on the substrate including the light emitting layer 570 and the auxiliary electrode 560 exposed by the via hole 557. The second electrode 580 may be an anode, and may be formed of a transparent conductive film having a high work function such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). Can be. Alternatively, the second electrode 580 may be formed using a thin film of magnesium (Mg), silver (Ag), aluminum (Al), or the like, and may further include a transparent conductive film to match the work function. have. The second electrode 580 is not patterned for each pixel, but is formed as a front electrode on the substrate 500.

In another embodiment of the present invention, the second electrode 580 is electrically connected to the auxiliary electrode 560 disposed under the fourth insulating layer 550 through the via hole 557. Since the auxiliary electrode 560 is formed to include a metal having a low resistance, the auxiliary electrode 560 serves to lower the sheet resistance of the second electrode 580 made of a transparent conductive film or a thin conductive film. Therefore, when driving the electroluminescent device, a signal delay due to the sheet resistance of the second electrode 580 can be prevented to make the luminance of each pixel uniform.

In addition, when the auxiliary electrode 560 is formed of a multi-layered film including chromium or chromium oxide, it can simultaneously play the role of a black matrix, thereby improving the visibility of the electroluminescent device.

In addition, since the auxiliary electrode according to another embodiment of the present invention is patterned at the same time as the first electrode, there is an advantage that the process is simple and does not use an additional mask.

As described above, the present invention has the effect of ensuring the uniformity and visibility of luminance for each pixel, thereby improving the quality of the screen.

Claims (20)

Board; A first electrode on the substrate; An insulating layer disposed on the first electrode and including an opening exposing a portion of the first electrode; An emission layer positioned in the opening; A second electrode on the light emitting layer; And An auxiliary electrode positioned in an arbitrary region of the lower or upper portion except the opening of the insulating layer and electrically connected to the second electrode, wherein the auxiliary electrode is one or more metal films including a metal film made of chromium or chromium oxide; Electroluminescent element composed. delete The method of claim 1, The auxiliary electrode is disposed under the insulating film, and is spaced apart from the first electrode between the first electrode. The method of claim 3, wherein The insulating layer may include a via hole for electrically connecting the auxiliary electrode and the second electrode. delete The method of claim 1, The auxiliary electrode is an electroluminescent device consisting of any one or more selected from the group consisting of aluminum, molybdenum, copper, tungsten, silver, nickel, gold and alloys thereof. delete The method of claim 1, The auxiliary electrode further comprises at least one metal oxide film. delete The method of claim 1, The first electrode is a cathode, and the second electrode is an anode. The method of claim 1, The light emitting layer is an electroluminescent device made of an organic material. The method of claim 1, And a thin film transistor electrically connected to the first electrode. Providing a substrate; Forming a first electrode on the substrate; Forming an insulating film on the first electrode, the insulating film including an opening exposing the first electrode; Forming an auxiliary electrode including a metal film made of chromium or chromium oxide on the insulating film except for the opening; Forming a light emitting layer on at least a portion of the auxiliary electrode on the insulating layer including the opening; Forming a second electrode on a substrate including the light emitting layer and the auxiliary electrode. The method of claim 13, The forming of the auxiliary electrode may be performed by performing a photolithography process. The method of claim 13, Forming the light emitting layer is a method of manufacturing an electroluminescent device formed by performing a vacuum deposition method using a shadow mask. The method of claim 13, And the auxiliary electrode is formed of a multilayer film. Providing a substrate; Forming an auxiliary electrode on the substrate, the auxiliary electrode including a metal film made of chromium or chromium oxide between the first electrodes to be spaced apart from the first electrode; Forming an insulating layer on the first electrode and the auxiliary electrode, the insulating layer including an opening exposing the first electrode and a via hole exposing the auxiliary electrode; Forming a light emitting layer to expose at least a portion of the via hole on the insulating layer including the opening; And forming a second electrode on the substrate including the light emitting layer to be electrically connected to the auxiliary electrode through the via hole. The method of claim 17, Forming the light emitting layer is a method of manufacturing an electroluminescent device formed by performing a vacuum deposition method using a shadow mask. The method of claim 18, The shadow mask manufacturing method of the electroluminescent device when the alignment with the substrate, at least a portion corresponding to at least a portion of the via hole and the blocking portion manufacturing method of the electroluminescent device. The method of claim 17, And the auxiliary electrode is formed of a multilayer film.

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