KR100611755B1 - Organic electroluminescent device and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an organic electroluminescent device and a method of manufacturing the same, and more particularly, to an organic electroluminescent device for improving the life of the organic light emitting device and a manufacturing method thereof.

The present invention provides a thin film transistor comprising an insulating substrate, a semiconductor layer, a source / drain electrode, and a gate electrode; A passivation film formed over the substrate including the thin film transistor and having a via hole for exposing one of the source / drain electrodes; A first electrode disposed on the passivation layer and connected to one of the source / drain electrodes through the via hole; A pixel definition layer pattern formed on an entire surface of the passivation layer including the first electrode and having an opening exposing a predetermined portion of the first electrode; A barrier layer positioned on the pixel definition layer pattern; An organic film disposed on the first electrode exposed through the opening and including at least an organic light emitting layer; An organic electroluminescent device comprising a second electrode formed on the organic film and a method of manufacturing the same are provided.

OLEDs, ions, inerts, barriers, pixel definition layers

Description

Organic electroluminescent device and method for manufacturing the same {organic electroluminuence device and method for fabricating the same}

FIG. 1 is a plan view illustrating a general organic light emitting display device and is limited to one pixel including red (R), green (G), and blue (B) unit pixels of the organic light emitting display device.

FIG. 2 is a cross-sectional view of an organic light emitting device in the organic light emitting device taken along the cutting line I-I 'of FIG.

3A to 3C are cross-sectional views illustrating an organic light emitting display device and a method of manufacturing the same according to an embodiment of the present invention.

4 is an actual photograph when an impurity is injected into the upper portion of the pixel definition layer.

(Explanation of symbols for main parts of drawing)

200: insulating substrate 225: semiconductor layer

245: source / drain electrode 265: first electrode

260: pixel defining layer 260 ': barrier layer

270: organic film 280: second electrode

The present invention relates to an organic electroluminescent device and a method of manufacturing the same, and more particularly, to an organic electroluminescent device and a method of manufacturing the same for improving the life characteristics of the organic electroluminescent device.

With the advent of the high information age, there is an increasing demand for fast and accurate information in the hand, and the development of a display device that is light and thin, easy to carry, and has high information processing speed is rapidly being made. Conventional CRTs have high weight, volume, and power consumption, and LCDs have technical limitations on process complexity, narrow viewing angles, contrast ratios, and large area.

On the other hand, the organic electroluminescent device is a self-luminous type in which electrons and holes are recombined in the organic light emitting layer to generate light by applying a voltage to the organic film including the organic light emitting layer. The process can be simplified, the response speed is the same as the CRT, and it is advantageous in terms of power consumption. Accordingly, organic electroluminescent devices are rapidly rising as next generation displays.

FIG. 1 is a plan view illustrating a general organic EL device and is limited to one pixel including red (R), green (G), and blue (B) unit pixels of the organic EL device.

Referring to FIG. 1, a scan line 10 arranged in one direction, a data line 20 intersecting while insulated from the scan line 10, and an intersecting and intersecting while insulated from the scan line 10 The common power supply voltage line 30 is positioned in parallel to 20. By the scan line 10, the data line 20 and the common power supply voltage line 30, a plurality of unit pixels, for example, red (R), green (G), and blue (B) unit pixels Is defined.

Each unit pixel includes a switching thin film transistor 50, a driving thin film transistor 60, a capacitor 70, and an organic light emitting diode 90.

Each unit pixel includes a data signal applied to the data line 20 according to a signal applied to the scan line 10, for example, a data voltage and a voltage difference applied to the common power line 30. The capacitor 70 accumulating the charges and the signal generated by the charges accumulated in the capacitor 70 are input to the driving thin film transistor 60 through the switching thin film transistor 50. Subsequently, the driving thin film transistor 60 receiving the data signal transmits an electrical signal to the organic light emitting device 90 having an organic light emitting layer between the first electrode 80, the second electrode, and the two electrodes to emit light. do.

FIG. 2 is a cross-sectional view of an organic light emitting diode in the organic electroluminescent device taken along the cutting line II ′ of FIG. 1.

Referring to FIG. 2, a substrate having red (R), green (G), and blue (B) unit pixel regions is provided.

After the first electrode 110 is formed on the insulating substrate 100, the pixel defining layer 120 is formed on the first electrode 110 over the entire surface of the substrate to define a pixel region in which the emission layer is to be formed. To form.

The pixel defining layer 120 is typically made of a photosensitive material, and forms an opening 125 that exposes a portion of the first electrode by a photolithography process.

Subsequently, a baking process is performed at 230 ° C. to 280 ° C. to cure the pixel definition layer 120 having the opening 125.

Subsequently, an organic electroluminescent device is manufactured by forming an organic layer 130 including at least an organic light emitting layer on the opening 125 over the entire surface of the substrate, forming a second electrode 140 thereon, and then encapsulating the organic electrode 130. do.

The organic layer 130 may be formed as a multilayer organic layer by laminating one or all of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer, and an electron injection layer in addition to the organic light emitting layer.

However, the pixel defining layer 120 may have an outgas generated due to short-term or long-term chemical decomposition to deteriorate the organic light emitting diode, and may have a fatal effect such as pixel shrinkage and lifespan deterioration. In addition, the pixel defining layer may be deformed to a structure in which organic molecules of the organic layer have no light emitting function by a functional group that may be generated at a high temperature, thereby greatly changing luminance and color.

To this end, although the inorganic film having the least influence as described above may be used as the pixel defining layer, there are difficulties in the process.

The technical problem to be achieved by the present invention is to solve the above-described problems of the prior art, by curing the upper portion of the pixel definition layer to provide a barrier layer to prevent the outgas is introduced into the organic light emitting device to improve the life characteristics An organic electroluminescent device and a method of manufacturing the same are provided.

According to an aspect of the present invention, there is provided a thin film transistor having an insulating substrate, a semiconductor layer, a source / drain electrode, and a gate electrode; A passivation film formed over the substrate including the thin film transistor and having a via hole for exposing one of the source / drain electrodes; A first electrode disposed on the passivation layer and connected to one of the source / drain electrodes through the via hole; A pixel definition layer pattern formed on an entire surface of the passivation layer including the first electrode and having an opening exposing a predetermined portion of the first electrode; A barrier layer positioned on the pixel definition layer pattern; An organic film disposed on the first electrode exposed through the opening and including at least an organic light emitting layer; It provides an organic electroluminescent device comprising a second electrode formed on the organic film.

In addition, the present invention provides a thin film transistor having a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, and a source / drain electrode on the buffer layer of the insulating substrate;

Forming a passivation film over the thin film transistor over the entire surface of the interlayer insulating film; Etching the passivation layer to form via holes for exposing the source / drain electrodes; Forming a first electrode in contact with the source / drain electrode through the via hole; Forming a pixel defining layer on an entire surface of the passivation layer including the first electrode; Patterning the pixel definition layer by a photolithography process to form an opening that partially exposes the first electrode; Implanting an impurity into the patterned pixel definition layer to form a barrier layer; Forming an organic film including at least a light emitting layer on the first electrode; It provides a method of manufacturing an organic electroluminescent device characterized in that the second electrode is formed on the organic film.

The pixel defining layer may prevent short circuits between the first electrode and the second electrode by preventing the organic layer from breaking or concentration of an electric field in the edge portion of the first electrode.

The pixel definition layer may be formed of polystyrene, polymethyl methacrylate, polyacrylonitrile, polyamide, polyimide, polyaryl ether, heterocyclic polymer, parylene, fluorine polymer, epoxy resin, benzocyclobutyne resin, It may be formed of one material selected from the group consisting of siloxane resin and silane resin.

In general, when impurities are injected into the polymer material, various physical properties such as hardness, electrical properties, and optical properties may be changed by surface modification of the polymer material.

Accordingly, by injecting impurities into the pixel definition layer and curing the upper layer of the pixel definition layer once more, it is possible to prevent the outgas generated inside the pixel definition layer from being emitted to the organic light emitting diode.

Here, the impurity may be one of ions consisting of P, B and As.

Injecting the ions into the pixel defining layer activates the functional groups of the polymer forming the pixel defining layer. For example, hydrogen atoms in the polymer are separated from the molecule to participate in the coupling reaction between the polymers, thereby causing cross linking coupling between the polymers. As a result, the spacing between the molecular chains becomes dense, which not only improves gas barrier properties but also increases hardness.

Accordingly, by injecting ions into the surface of the pixel defining layer, the barrier layer can be formed by curing the surface of the pixel defining layer once more. In addition, the degree of crosslinking between polymers can be increased to increase chemical resistance and durability.

In addition, the impurities may be one of the inert gases made from the group of Ar, He, Xe, H ₂ and Ne.

The barrier layer may be formed by accelerating the inert gas on the pixel definition layer through surface modification of the pixel definition layer.

Hereinafter, the structure and manufacturing method of the organic light emitting display device according to the present invention will be described in detail with reference to FIGS. 3A to 3D.

3A to 3D are cross-sectional views illustrating an organic EL device and a method of manufacturing the same according to an embodiment of the present invention.

Referring to FIG. 3A, a buffer layer 210 selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxide film / silicon nitride film is provided to provide a transparent insulating substrate and prevent impurities from flowing out from the insulating substrate 200. It is preferable to include.

 An amorphous silicon film is coated on the buffer layer 210, crystallized, and then patterned to form a polysilicon film 225.

After the gate insulating film 220 is formed over the entire surface of the polysilicon film 225, a predetermined portion of the gate insulating film 220, that is, a portion facing the channel region 225b is formed. The gate electrode 235 is deposited.

Thereafter, the polysilicon layer 225 is ion-doped to form a semiconductor layer 225 including the drain region 225a, the source region 225c, and the channel region 225b.

An interlayer insulating film 230 is formed over the gate insulating film 220 on the gate electrode 235, and the drain insulating film 225a and the source region 225c are etched by etching the gate insulating film 220 and the interlayer insulating film 230. A contact hole is formed to expose a predetermined portion.

Source / drain electrodes 245 connected to the source / drain regions 225c and 225a are formed on the interlayer insulating layer 230 through the contact holes.

The passivation insulating layer 240 covering the source / drain electrodes 245 is formed on the entire surface of the interlayer insulating layer 230. The passivation insulating layer 240 may be selected from one of SiO ₂ , SiNx, and SiO ₂ / SiNx laminates.

The planarization layer 250 may be further included on the passivation insulating layer 240 to planarize the step by the thin film transistor. Here, the planarization layer 250 may prevent diffuse reflection caused by the step difference of the thin film transistor as the organic layer is thinly formed in a subsequent process.

The planarization layer 250 may be formed of one material selected from the group consisting of polyamide resin, polyimide resin, acrylic resin, and silicone resin.

Subsequently, a via hole 255 is formed on the planarization film 250 to expose one of the source / drain electrodes 245, and the planarization is performed on the source / drain electrode 245 exposed by the via hole 255. A first electrode 265 is formed over the entire surface of the film 250.

Here, when the first electrode 265 is an anode, a metal having a high work function is a transparent electrode made of ITO or IZO, or made of Pt, Au, Ir, Cr, Mg, Ag, Ni, Al, and an alloy thereof. It may be a reflective electrode selected from the group.

In addition, when the first electrode 265 is a cathode, a metal having a low work function is selected from the group consisting of Mg, Ca, Al, Ag, Ba, and alloys thereof. Can be.

A pixel definition layer 260 is formed on the entire surface of the substrate on which the first electrode 265 is formed to sufficiently cover the curved first electrode.

Here, the pixel definition layer may be applied to 1 to 3㎛ by spin coating or dip coating method.

In addition, the pixel defining layer 260 is a polystyrene, polymethyl methacrylate, polyacrylonitrile, polyamide, polyimide, polyaryl ether, heterocyclic polymer, parylene, fluorine polymer, epoxy resin, It may be formed of one material selected from the group consisting of benzocyclobutyne resin, siloxane resin and silane resin.

 Thereafter, as illustrated in FIG. 3B, the pixel defining layer 260 formed on the first electrode 265 is patterned through a conventional photolithography process to form an opening A exposing a predetermined portion of the first electrode. .

The pattern 260 of the pixel definition layer is cured through a baking process at a temperature of 230 to 260 ° C., and the outgas remaining in the inside is removed, but the outgas cannot be completely removed, which may adversely affect the organic light emitting device. .

Accordingly, the barrier layer 260 ′ is formed by hardening the surface of the pixel definition layer once more by injecting impurities X into the upper portion of the pixel definition layer pattern 260.

Here, the impurity (X) may be one of the ions consisting of B, P, As, etc., wherein the ions are implanted at an acceleration energy of 75 to 85 KeV using an ion implanter or an implanter, for example. It is preferable to inject a dose of 1 × e ¹⁴ to 1 × e ¹⁵ ions / cm 2.

On the other hand, the impurity (X) may be one of the inert gas consisting of Ar, He, Xe, H ₂ and Ne, etc., the inert gas is a device capable of sputtering, for example, an etcher (etcher) or an asher (asher) It is preferable to accelerate a gas of 50 sccm or more to the pixel defining layer pattern in a vacuum of 10 to 400 mtorr at a power of 100 W.

Here, as the barrier layer 260 'is formed thicker, it is possible to prevent the outgas from being released into the organic layer. However, in order to form the barrier layer thick, it is possible to use high energy or increase the impurity concentration. However, these processes require expensive equipment or require more time to invest, which can result in lower productivity and increased production costs.

Accordingly, the barrier layer formed after the impurity doping is preferably formed to be 10% or less of the thickness of the pixel definition layer.

Next, as illustrated in FIG. 3C, an organic layer including an organic emission layer that emits red, green, and blue light by the flow of electric current through the entire surface of the first electrode 265 and the pixel defining layer pattern 260 ( 270). The organic layer 270 may further include one or both of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer, and an electron injection layer.

Thereafter, a second electrode 280 is formed on the organic layer 270 in the light emitting device layer.

In the case where the second electrode 280 is a cathode, a conductive metal formed on the organic layer 270 and having a low work function is selected from the group consisting of Mg, Ca, Al, Ag, and alloys thereof. It is formed of a transparent electrode having a thin thickness as a material of, or a reflective electrode having a thick thickness.

In addition, when the second electrode 280 is an anode, the metal having a high work function is a transparent electrode made of ITO or IZO, or Pt, Au, Ir, Cr, Mg, Ag, Ni, Al, and the like. It may be a reflective electrode made of an alloy.

Then, the organic electroluminescent device can be manufactured by sealing with an encapsulant such as an upper metal can.

4 is an actual photograph when an impurity is injected into the upper portion of the pixel definition layer.

As shown in FIG. 4, the barrier layer 300 having a thickness of 2800 μs is hardened once more by injecting P ions into the pixel definition layer formed on the substrate at a dose of 1 × e ¹⁵ ions / cm 2 with an acceleration energy of 75 KeV. It could be confirmed that it forms.

As a result, a barrier layer may be formed by injecting impurities without a separate mask process to solve problems such as deterioration of organic elements and pixel reduction due to outgassing.

In addition, since the thermal deformation stress of the pixel definition layer due to the external environment, for example, due to temperature can be minimized, the life of the organic device can be improved.

As described above, according to the present invention, by partially curing the upper portion of the pixel definition layer, it serves as a gas barrier, thereby preventing outgassing into the organic light emitting device, thereby preventing degradation of the organic light emitting device and pixel reduction. The lifetime of the organic light emitting device can be improved.

Claims (25)

A thin film transistor having an insulating substrate, a semiconductor layer, a source / drain electrode, and a gate electrode; A passivation film formed over the substrate including the thin film transistor and having a via hole for exposing one of the source / drain electrodes; A first electrode disposed on the passivation layer and connected to one of the source / drain electrodes through the via hole; A pixel definition layer pattern formed on an entire surface of the passivation layer including the first electrode and having an opening exposing a predetermined portion of the first electrode; A barrier layer positioned on the pixel definition layer pattern; An organic film disposed on the first electrode exposed through the opening and including at least an organic light emitting layer; An organic electroluminescent device comprising a second electrode formed on the organic film. The method of claim 1, And the first electrode is an anode or a cathode. The method of claim 1, The pixel definition layer is polystyrene, polymethyl methacrylate, polyacrylonitrile, polyamide, polyimide, polyarylether, heterocyclic polymer, parylene, fluorine polymer, epoxy resin, benzocyclobutyne resin, siloxane An organic electroluminescent device, characterized in that it is formed of one material selected from the group consisting of resins and silane resins. The method of claim 1, The pixel definition layer is formed with a thickness of 1 to 3㎛ organic electroluminescent device. The method of claim 1, And the barrier layer is formed to be greater than 0 and 10% or less with respect to the pixel definition layer thickness. The method of claim 1, The barrier layer is organic electroluminescent device, characterized in that formed by curing with impurities. The method of claim 6, The impurity is an organic electroluminescent device, characterized in that consisting of ions or inert gas. The method of claim 7, wherein The ion is an organic electroluminescent device, characterized in that formed by injecting one ion selected from the group consisting of B, P and As. The method of claim 7, wherein The inert gas is formed by accelerating one inert gas selected from the group consisting of Ar, He, Xe, H ₂ and Ne. The method of claim 1, The organic electroluminescent device further comprises a planarization film on the passivation film. The method of claim 1, And the organic layer further comprises at least one selected from the group consisting of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer, and an electron injection layer. Forming a thin film transistor having a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, and a source / drain electrode over the buffer layer of the insulating substrate; Forming a passivation film over the thin film transistor over the entire surface of the interlayer insulating film; Etching the passivation layer to form via holes for exposing the source / drain electrodes; Forming a first electrode in contact with the source / drain electrode through the via hole; Forming a pixel defining layer covering the first electrode; Patterning the pixel definition layer by a photolithography process to form an opening that partially exposes the first electrode; Implanting an impurity into the patterned pixel definition layer to form a barrier layer; Forming an organic film including at least a light emitting layer on the pixel electrode; A method of manufacturing an organic electroluminescent device, characterized in that a second electrode is formed on the organic film. The method of claim 12, The first electrode is an anode or a cathode, characterized in that the manufacturing method of the organic electroluminescent device. The method of claim 12, The pixel definition layer is polystyrene, polymethyl methacrylate, polyacrylonitrile, polyamide, polyimide, polyarylether, heterocyclic polymer, parylene, fluorine polymer, epoxy resin, benzocyclobutyne resin, siloxane A method for producing an organic electroluminescent device, characterized in that it is formed of one material selected from the group consisting of resins and silane resins. The method of claim 12, The pixel defining layer is formed with a thickness of 1 to 3㎛ by spin coating or dip coating. The method of claim 12, The impurity is a method of manufacturing an organic electroluminescent device, characterized in that the ion or inert gas. The method of claim 16, The ion is a method of manufacturing an organic electroluminescent device, characterized in that one of B, P and As. The method of claim 16, The ion implantation method of manufacturing an organic electroluminescent device, characterized in that formed using an ion shower or implant. The method of claim 16, The ion is a method of manufacturing an organic electroluminescent device, characterized in that the implanted dose of 10 ¹⁴ to 10 ¹⁵ ions / ㎠ at an acceleration energy of 75 to 85 keV to the upper portion of the pixel definition layer. The method of claim 16, The inert gas is one of Ar, He, Xe, H ₂ and Ne is a manufacturing method of the organic electroluminescent device, characterized in that one selected from the group consisting of. The method of claim 16, The inert gas is an organic electroluminescent device, characterized in that the accelerator (etcher) or an accelerator (asher) is accelerated on the upper portion of the pixel definition layer. The method of claim 16, The inert gas is a method of manufacturing an organic electroluminescent device, characterized in that the gas of at least 50sccm is accelerated to the upper portion of the pixel definition layer in a vacuum of 10 to 400 mtorr with a power of 100W. The method of claim 12, The barrier layer may be formed to be greater than 0 and less than or equal to 10% of the pixel definition layer thickness. The method of claim 12, The organic electroluminescent device further comprises a planarization film on the passivation film. The method of claim 12, The organic layer may further include at least one selected from the group consisting of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer, and an electron injection layer.

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