KR20060055212A - Fabricating method of organic electroluminescence display device - Google Patents

Abstract

The present invention relates to a method of manufacturing an organic light emitting display device, and more particularly, by depositing an aluminum oxide (Al ₂ O ₃ ) film, which is an inorganic protective film layer, on a second electrode at a low temperature process, without damaging the organic light emitting layer. The present invention relates to a method of manufacturing an organic light emitting display device which prevents cracking and corrosion of a second electrode when water is introduced from the gas and when gas is introduced due to a poor moisture absorbent.

Organic electroluminescent device, inorganic protective film layer, aluminum oxide film, bad moisture absorbent

Description

Fabrication Method of Organic Electroluminescence Display Device

1 is a cross-sectional view for explaining an organic light emitting display device and a method of manufacturing the same according to the prior art.

2 is a cross-sectional view illustrating an organic light emitting display device and a method of manufacturing the same according to an embodiment of the present invention.

FIG. 3 is a photograph of a focused ion beam (FIB) showing a crack phenomenon of an aluminum (Al) film as a second electrode.

<Description of the symbols for the main parts of the drawings>

300 substrate 310 first electrode

320: pixel definition layer 330: organic layer

340: hole injection layer 350: hole transport layer

360: organic light emitting layer 370: electron transport layer

380: electron injection layer 390: second electrode

400: inorganic protective film layer 410: moisture absorbent

420: sealing substrate

The present invention relates to a method of manufacturing an organic light emitting display device, and more particularly, by depositing an aluminum oxide (Al ₂ O ₃ ) film, which is an inorganic protective film layer, on a second electrode of an organic light emitting display device in a low temperature process, thereby introducing moisture from the outside. The present invention relates to a method of manufacturing an organic light emitting display device, which prevents cracking and corrosion of a second electrode during penetration and gas inflow due to a poor absorbent.

In general, an organic electroluminescence display (OLED) among flat panel display devices (OLED) is a self-luminous display device that electrically excites an organic compound to emit light and does not require a backlight such as an LCD. Not only can it be thin, it can simplify the process, it can be manufactured at low temperature, it has a fast response time with a response speed of 1ms or less, low power consumption, wide viewing angle due to self-luminous, high contrast, etc. It is attracting attention as a next-generation flat panel display device by showing characteristics.

In general, an organic light emitting display device includes an organic light emitting layer between an anode electrode and a cathode electrode, so that holes supplied from the anode electrode and electrons received from the cathode electrode combine in the organic light emitting layer to form a hole-electron pair excitons, and then the exciton Is emitted by the energy generated when returning to the ground state.

1 is a cross-sectional view for explaining an organic light emitting display device and a method of manufacturing the same according to the prior art.

Referring to FIG. 1, a conventional organic light emitting display device is formed by patterning a first electrode 110 on a transparent substrate 100 made of glass or plastic. In the case of the anode, the first electrode 110 is a transparent electrode made of indium tin oxide (ITO) or indium zinc oxide (IZO) having a high work function, or has a high reflectivity such as aluminum or an aluminum alloy in a lower layer. It may be a transparent electrode including a reflective film made of a metal having a. When the first electrode is a cathode, a conductive metal having a low work function is a material selected from the group consisting of Mg, Ca, Al, Ag, and alloys thereof. It is formed of a reflective electrode having a thickness.

A pixel definition layer (PDL) 120 is formed on the first electrode 110 as an insulating material to define a pixel region and to insulate the organic light emitting layer. The pixel defining layer 120 is typically made of polyimide (PI), polyamide (PA), acrylic resin (Acryl Resin), benzocyclobutene (BCB), and phenolic resin as an organic type. It is formed of one species selected from the group.

The pixel definition layer 120 is deposited on the substrate by a spin coating method. Subsequently, the pixel defining layer 120 has an opening that exposes a portion of the surface of the first electrode 110 through etching.

Subsequently, an organic layer 130 including at least an organic emission layer (EML) 160 is formed on the exposed pixel defining layer 120 of the first electrode 110. In addition to the organic light emitting layer 160, a hole injection layer (HIL) 140, a hole transport layer (HTL) 150, an electron transport layer (ETL) 170, and an electron injection layer ( It may further include one or more layers of EIL (Electron Injection Layer) 180.

The organic light emitting layer 160 may be made of a low molecular material such as aluminy chinolium complex (Alq3), cyclo pentadiene and anthracene, or poly (p-phenylenevinylene) (PPV; poly- (p- phenylenevinylene)) and derivatives thereof, polythiophene (PT) and derivatives thereof, and polyvinylene (PPP; polyphenylene) and derivatives thereof. The organic layer 130 is patterned after being formed by a spin coating method or a vacuum deposition method.

Subsequently, a second electrode 190 is formed over the entire upper surface of the organic layer 130. The second electrode 190 is a conductive metal having a low work function and made of Mg, Ca, Al, Ag, and alloys thereof when the first electrode 110 is an anode transparent electrode or a transparent electrode including a reflective film. One kind of material selected from the group is formed of a reflective electrode or a transparent electrode having a thin thickness, and when the first electrode 110 is a cathode, it is formed of a transparent electrode such as ITO or IZO or a transparent electrode including a reflective film. . The second electrode 190 is formed by a vacuum deposition method.

Subsequently, the encapsulation substrate 220 having the moisture absorbent 210 attached to the second electrode 190 is bonded to the lower substrate to complete the organic light emitting diode.

When the conventional second electrode 190 is aluminum (Al), aluminum (Al) is deposited by an ion beam assisted deposition (IBAD) method. When aluminum (Al) is deposited using the IBAD method, the aluminum (Al) is densely deposited to crack and corrode phenomena of aluminum (Al) when water is introduced from the outside and gas is introduced due to poor moisture absorbent. You can prevent it. However, the IBAD method has a problem in that the organic light emitting layer 160 is damaged by the ion beam, and thus the life is reduced.

The technical problem to be achieved by the present invention is to solve the above problems of the prior art, by depositing an inorganic protective film layer on the second electrode of the organic light emitting device by a low temperature process, without damaging the organic light emitting layer from the outside The present invention provides a method of manufacturing an organic light emitting display device which prevents cracking and corrosion of the second electrode when water is introduced and gas is introduced due to a poor moisture absorbent.

In order to achieve the above technical problem, the present invention

Providing a substrate;

Forming a first electrode on the substrate;

Forming an organic layer including at least an organic light emitting layer on the first electrode;

Forming a second electrode on the organic layer;

Forming an inorganic protective film layer formed of an aluminum oxide (Al ₂ O ₃ ) film on the second electrode; And

It provides a method of manufacturing an organic light emitting display device comprising the step of bonding the encapsulation substrate with a moisture absorbent on the inorganic protective film layer and the substrate.

Hereinafter, with reference to the accompanying drawings of the present invention will be described in more detail.

2 is a cross-sectional view illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 2, the organic light emitting diode of the present invention is formed by patterning a substrate 300 and a first electrode 310 on the substrate. The substrate 300 is a transparent substrate such as glass, plastic and quartz. The first electrode 310 is deposited by sputtering or ion plating. More preferably, the first electrode 310 is formed by selectively patterning through wet etching using a photoresist (PR; Photo Resist) patterned in a photolithography process after deposition by a sputtering method as a mask.

The first electrode 310 may be a transparent electrode made of ITO or IZO having a high work function in the case of an anode, or a transparent electrode including a reflective film made of a metal having high reflectivity such as aluminum or an aluminum alloy in a lower layer. have. When the first electrode 310 is a cathode, a conductive metal having a low work function is a material selected from the group consisting of Mg, Ca, Al, Ag, and alloys thereof. It is formed of a reflective electrode having a thickness. Preferably, the first electrode 310 is formed of a transparent electrode including an anode electrode or a transparent electrode.

The pixel definition layer 320 may be further formed over the entire upper surface of the substrate including the first electrode 310. The pixel defining layer 320 is typically an organic based polyimide (PI), polyamide (PA), acrylic resin (Acryl Resin), benzocyclobutene (BCB) and phenol resin ( Phenolic Resin) is formed from one selected from the group consisting of.

The pixel defining layer 320 is stacked on the substrate by a spin coating method, and formed to have an opening that exposes a portion of the surface of the first electrode 310 through etching. In this case, the pixel defining layer 320 is selectively removed in an etching process using a photoresist pattern formed in a photo process, and then transferred to a substrate according to a pattern designed for a reticle.

Subsequently, an organic layer 330 including at least an organic light emitting layer 360 is formed on the exposed first electrode 310. The organic layer 330 may further include at least one of the hole injection layer 340, the hole transport layer 350, the electron transport layer 370, and the electron injection layer 380, in addition to the organic light emitting layer 360.

 The organic light emitting layer 360 may be a low molecular material or a high molecular material. The low molecular weight material is one selected from the group consisting of aluminy quinolium complex (Alq3), anthracene (Anthracene), cyclo pentadiene (Cyclo pentadiene), BeBq2, Almq, ZnPBO, Balq, DPVBi, BSA-2 and 2PSP Form.

The polymer material is poly (p-phenylenevinylene) (PPV; poly (p-phenylenevinylene)) and its derivatives, polythiophene (PT) and its derivatives and polyphenylene (PPP; Polyphenylene) and its derivatives It is formed of one selected from the group consisting of.

The hole injection layer 340 may include phthalocyanine copper (CuPc: Copper Phthalocyanine), PEDOT, m-MTDATA, triphenylamine, benzidine, hydrazine, pyrazoline, and styrylamine. (Styrylamine), carbazole (Carbazole), triphenylmethane (Triphenymethane) is selected from one type.

The hole transport layer 350 comprises one or more hole transport compounds, for example aromatic tertiary amines, which contain one or more trivalent nitrogen atoms bonded only to carbon atoms (one or more of which are members of the aromatic ring) It is a compound. In one form, the aromatic tertiary amine may be an arylamine such as monoarylamine, diarylamine, triarylamine or polymeric arylamine.

Preferred thin film forming materials useful for forming the electron transport layer 370 are metal chelated oxy comprising chelates of auxin itself (commonly referred to as '8-quinolinol' or '8-hydroxyquinoline'). Noide compound. Such compounds help to inject and transport electrons, exhibit high levels of performance, and are readily prepared in the form of thin films. Other electron transport materials include butadiene derivatives, heterocyclic optical brighteners. Benzazole and triazine are also useful electron transport materials. In addition, when a dopant is applied to a light emitting layer, an aluminy quinolium composite (Alq3), which is used as a host material of the light emitting layer, also has characteristics as an electron transporter, and thus is widely used.

The organic layer 330 is formed by depositing by vacuum deposition, spin coating, inkjet printing, a doctor blade, a laser induced thermal imaging (LITI) method, or the like. Meanwhile, the organic layer 330 may be patterned for each unit pixel. Patterning the organic layer 330 may be implemented using a laser thermal transfer method, a vacuum deposition method using a shadow mask, or the like.

Subsequently, a second electrode 390 is formed on the organic layer 330.

When the first electrode 310 is an anode transparent electrode or a transparent electrode including a reflective film, the second electrode 390 is a conductive metal having a low work function and made of Mg, Ca, Al, Ag, and alloys thereof. One material selected from the group is formed as a reflective electrode or a transparent electrode having a thin thickness, and when the first electrode 310 is a cathode, it is formed as a transparent electrode including a transparent electrode such as ITO or IZO or a reflective film. Preferably, the second electrode 390 is made of aluminum (Al).

The aluminum (Al) is deposited by thermal evaporation in order not to damage the organic light emitting layer 360. When the aluminum (Al) is deposited by the ion beam assisted deposition (IBAD) method, the organic light emitting layer may be damaged by the ion beam, and the organic light emitting layer may be damaged by the physical force during the deposition by the sputtering method.

FIG. 3 is a photograph of a focused ion beam (FIB) showing a crack phenomenon of an aluminum (Al) film as a second electrode.

Referring to FIG. 3, ITO, the first electrode 310, the organic light emitting layer 360, and aluminum (Al), the second electrode 390, are deposited, and the aluminum (Al) film may penetrate moisture from the outside and It can be seen that the cracking of the membrane occurred severely due to the gas inflow due to the poor moisture absorbent formed in the subsequent process.

The passivation layer 400 is formed on the second electrode 390 to prevent cracking of the aluminum Al that is the second electrode 390. The protective film layer 400 is formed of an inorganic film. Preferably, the inorganic film is formed of an aluminum oxide (Al ₂ O ₃ ) film.

The aluminum oxide (Al ₂ O ₃ ) has a dense structure and is formed by sputtering. The second electrode 390 may be deposited by adding O ₂ gas in the sputtering process, even at low temperatures.

In general, the sputtering method injects argon (Ar) gas, which is an inert gas, into a plasma state in a process chamber to which a high voltage is applied to form a metal on a substrate, and then accelerates the collision force between ions. A metal material (target) to be deposited is deposited on a substrate. At this time, the sputtering method irradiates the target with accelerated ions, the ions enter the target and collide with the atoms or molecules constituting the target, and gradually lose energy and stop. Repeat to form a metal film using sputter evaporation in which the atoms or molecules on the surface is released to the outer space.

For example, ions are accelerated to collide with one another to protrude metal atoms from a target made of aluminum (Al), titanium (Ti), or the like to deposit a metal thin film on a substrate to form an electrode or wiring.

In the sputtering process of forming the aluminum oxide (Al ₂ O ₃ ) film 400, the temperature is 80 ° C. to 100 ° C. When the temperature is 80 ° C. or less, the aluminum oxide (Al ₂ O ₃ ) film is not properly formed, and when the temperature is 100 ° C. or more, the organic light emitting layer having low thermal stability may be damaged.

The aluminum oxide (Al ₂ O ₃ ) film 400 has a thickness of 100 kPa to 6000 kPa. When the thickness of the aluminum oxide (Al ₂ O ₃ ) film is less than 100 μs, cracks and corrosion of aluminum (Al) cannot be prevented during water ingress from the outside and gas inflow due to poor moisture absorbents. In the above case, the organic light emitting layer serving as the lower layer is stressed by the weight of the deposited aluminum oxide (Al ₂ O ₃ ) film.

As a result, an aluminum oxide (Al ₂ O ₃ ) film, which is an inorganic protective film layer, is deposited on the second electrode in a low temperature process of 80 ° C. to 100 ° C., so that the organic light emitting layer does not damage the organic light emitting layer and subsequently penetrates moisture. Prevents cracking and corrosion of the second electrode when the gas is introduced due to the poor moisture absorbent formed in the process.

Subsequently, the encapsulation substrate 420 having the moisture absorbent 410 attached to the inorganic passivation layer 400 is bonded to the substrate formed up to the second electrode 390.

The absorbent 410 is typically selected from the group consisting of alumina, bauxite, calcium sulfate, mud, silica gel, zeolite, alkali metal oxide, alkaline earth metal oxide, sulfate, or metal halide and perchlorate in an inert atmosphere such as nitrogen or argon. It is formed into one kind.

The encapsulation process is formed to protect the organic light emitting device from external moisture and oxygen, and organic material using a UV curing agent in an atmosphere of nitrogen / dry to prevent deterioration by moisture and oxygen. Formed through membrane and metal capsule. In this case, a polymer material such as polyparaxylene or an inorganic metal compound such as SiO ₂ , MgF ₂ , or In ₂ O ₃ may be applied for protection, or a polymer film or an SUS thin film may be used for encapsulation. As the evaporation source, a low resistance heating method using a tungsten source (boat), an electron beam evaporation source, a sputter evaporation source and the like are mainly used.

In more detail, the encapsulation process may include sealing cover cleaning, desiccant & film attachment process, UV sealant dispensing, adhesion with a film-forming substrate, and UV light curing. It proceeds to, thereby completing the organic light emitting device.

According to the present invention, an aluminum oxide (Al ₂ O ₃ ) film, which is an inorganic protective film layer, is deposited on a second electrode of an organic light emitting diode, so that the organic light emitting layer does not cause damage to the organic light emitting layer, and when the moisture penetrates from the outside and the gas due to poor moisture absorbent. It is possible to prevent cracking and corrosion of the second electrode during the inflow.

Claims (15)

Providing a substrate; Forming a first electrode on the substrate; Forming an organic layer including at least an organic light emitting layer on the first electrode; Forming a second electrode on the organic layer; Forming an inorganic protective film layer formed of an aluminum oxide (Al ₂ O ₃ ) film on the second electrode; And And bonding the encapsulation substrate having a moisture absorbent on the inorganic protective film layer to the substrate. The method of claim 1, The aluminum oxide (Al ₂ O ₃ ) film is formed by a sputtering method of manufacturing an organic light emitting display device. The method of claim 2, The method of manufacturing an organic light emitting display device, characterized in that the deposition by the addition of O ₂ gas in the sputtering process. The method of claim 2, Temperature in the sputtering process is a method of manufacturing an organic light emitting device, characterized in that 80 ℃ to 100 ℃. The method of claim 1, The thickness of the aluminum oxide (Al ₂ O ₃ ) film is a method of manufacturing an organic electroluminescent device, characterized in that 100 ~ 6000 Å. The method of claim 1, The first electrode is an anode, the second electrode is a method of manufacturing an organic light emitting device. The method of claim 6, The first electrode is a transparent electrode made of ITO or IZO or a transparent electrode comprising a reflective electrode made of a metal having a high reflectance characteristics such as aluminum or aluminum alloy. The method of claim 6,  The second electrode is a material selected from the group consisting of Mg, Ca, Al, Ag and alloys thereof, the method of manufacturing an organic electroluminescent device, characterized in that the reflective electrode or a thin-walled transmission electrode. The method of claim 8, The second electrode is a method of manufacturing an organic light emitting device, characterized in that the aluminum (Al). The method of claim 9, The aluminum (Al) is a method of manufacturing an organic light emitting device, characterized in that the deposition by thermal evaporation (Thermal Evaporation) method. The method of claim 1, The organic light emitting layer is a method of manufacturing an organic light emitting device, characterized in that formed of a low molecular material or a polymer material. The method of claim 11, The low molecular weight material is one selected from the group consisting of aluminy quinolium complex (Alq3), anthracene (Anthracene), cyclo pentadiene (Cyclo pentadiene), BeBq2, Almq, ZnPBO, Balq, DPVBi, BSA-2 and 2PSP Forming an organic electroluminescent device characterized in that it is formed. The method of claim 11, The polymer material is poly (p-phenylenevinylene) (PPV; poly (p-phenylenevinylene)) and its derivatives, polythiophene (PT) and its derivatives and polyphenylene (PPP; Polyphenylene) and its derivatives Method for producing an organic light emitting device, characterized in that formed in one kind selected from the group consisting of. The method of claim 1, The organic layer may further include at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer in addition to the organic light emitting layer. The method of claim 1, The hygroscopic agent is an alumina, bauxite, calcium sulfate, mud, silica gel, zeolite, alkali metal oxide, alkaline earth metal oxide, sulfate, or the production of an organic light emitting device, characterized in that one selected from the group consisting of metal halides and perchlorates. Way.

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