KR20100006465A - Organic light emitting display and manufacturing method for the same - Google Patents

Abstract

PURPOSE: An organic electroluminescent display device and a manufacturing method thereof are provided to improve constriction of a sub pixel due to outgassing by forming a bank layer for defining a light emitting region of a sub pixel using an organic material. CONSTITUTION: A buffer layer(111), a gate(112), a first insulation layer(113) and an active layer(114) are formed on a substrate(110). The active layer includes a channel region, a source region, and a drain region. A source(115a) and a drain(115b) are positioned on the active layer. A second insulation layer(116a) is positioned on the source and the drain. A third insulation layer(116b) is formed on the second insulation layer. A bottom electrode(117) is positioned on the third insulation layer. A bank layer(120) is positioned on the lower electrode. A buffer layer(121) is positioned on the bank layer.

Description

Organic Light Emitting Display and Manufacturing Method for the Same

The present invention relates to an organic light emitting display device and a manufacturing method thereof.

The organic light emitting display device used in the organic light emitting display device was a self-light emitting device having a light emitting layer formed between two electrodes.

In the organic light emitting device, electrons and holes are injected into the light emitting layer from an electron injection electrode and a hole injection electrode, respectively, and an exciton in which the injected electrons and holes combine is excited. The device emits light when it falls from the ground state to the ground state.

An organic light emitting display device using an organic light emitting display device includes a top emission type, a bottom emission type, and a dual emission type according to a direction in which light is emitted. According to this, it is divided into passive matrix type and active matrix type.

The organic light emitting display device is formed through a manufacturing process in which a deposition process and an etching process are performed in parallel to form a transistor, a capacitor, and an organic light emitting diode on a substrate.

On the other hand, the conventional organic light emitting display has a problem that the sub-pixel shrinks due to an out-gassing problem by the organic bank layer defining the light emitting region of the sub-pixel by exposing the lower electrode on the transistor. In addition, when the lower electrode is formed of a material vulnerable to oxidation, there is a problem that the bank layer is damaged when the oxide film formed on the lower electrode is removed.

Therefore, the conventional organic light emitting display device has to be prepared to solve such a problem.

SUMMARY OF THE INVENTION An object of the present invention for solving the above-described problems of the background art is to solve the problem of contracting a subpixel by outgassing generated from a bank layer formed of an organic material to define a light emitting region of a subpixel. The present invention provides an organic light emitting display device capable of forming a covering buffer layer to improve device life and reliability.

The present invention as a means for solving the above problems, the present invention comprises a transistor comprising a gate, a source and a drain; A lower electrode located on the transistor and connected to the source or drain of the transistor; A bank layer on the lower electrode and exposing the lower electrode; A buffer layer covering the bank layer and exposing the lower electrode; An organic light emitting layer on the lower electrode; And an upper electrode positioned on the organic light emitting layer.

The buffer layer is formed of an inorganic material.

On the other hand, in another aspect, the present invention, a transistor forming step comprising a gate, a source and a drain on the substrate; Forming a lower electrode connected to the source or the drain on the transistor; Forming a bank layer on the lower electrode to expose the lower electrode; Forming a buffer layer on the bank layer to cover the bank layer and expose the lower electrode; Forming an organic emission layer on the lower electrode; And forming an upper electrode on the organic light emitting layer.

When the lower electrode is a cathode, an oxide film removing process of removing the oxide film formed on the surface of the lower electrode may be performed after forming the inorganic buffer layer.

The buffer layer is formed of an inorganic material.

The present invention improves the lifetime and reliability of the device by forming a buffer layer covering all of the bank layers in order to solve the problem that the subpixels contract by the outgassing generated from the bank layer formed of the organic material to define the emission region of the subpixels. There is an effect to provide an organic light emitting display device that can be made. In addition, according to the present invention, when the lower electrode is formed of a material that is oxidized, the buffer layer has an effect of acting as a protective film that can prevent the bank layer from being damaged when the oxide film located on the lower electrode is removed.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

First Embodiment

1 illustrates a cross-sectional view of an organic light emitting display device according to a first embodiment of the present invention, and FIG. 2 illustrates a hierarchical structure of an organic light emitting diode.

Referring to FIG. 1, the substrate 110 may be selected as a material for forming an element having excellent mechanical strength or dimensional stability. As the material of the substrate 110, a glass plate, a metal plate, a ceramic plate or a plastic plate (polycarbonate resin, acrylic resin, vinyl chloride resin, polyethylene terephthalate resin, polyimide resin, polyester resin, epoxy resin, silicone resin, fluorine) Resin, etc.) is mentioned.

The buffer layer 111 may be positioned on the substrate 110. The buffer layer 111 may be formed to protect the thin film transistor formed in a subsequent process from impurities such as alkali ions flowing out of the substrate 110. The buffer layer 111 may use silicon oxide (SiO ₂ ), silicon nitride (SiNx), or the like.

The gate 112 may be located on the buffer layer 111. The gate 112 is selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be made of one or an alloy thereof. In addition, the gate 112 is formed of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be a multilayer made of any one or alloys thereof. In addition, the gate 112 may be a bilayer of molybdenum / aluminum-neodymium or molybdenum / aluminum.

The first insulating layer 113 may be positioned on the gate 112. The first insulating layer 113 may be, but is not limited to, a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), or multiple layers thereof.

The active layer 114 may be positioned on the first insulating layer 113. The active layer 114 may include amorphous silicon or polycrystalline silicon crystallized therefrom. Although not illustrated, the active layer 114 may include a channel region, a source region, and a drain region, and the source region and the drain region may be doped with P-type or N-type impurities. In addition, the active layer 114 may include an ohmic contact layer to lower the contact resistance.

The source 115a and the drain 115b may be positioned on the active layer 114. The source 115a and the drain 115b may be formed of a single layer or multiple layers. When the source 115a and the drain 115b are a single layer, molybdenum (Mo), aluminum (Al), chromium (Cr), and gold may be used. (Au), titanium (Ti), nickel (Ni), neodymium (Nd) and copper (Cu) may be made of any one or an alloy thereof. In addition, when the source 115a and the drain 115b are multiple layers, the double layer of molybdenum / aluminum-neodymium and the triple layer of molybdenum / aluminum / molybdenum or molybdenum / aluminum-neodymium / molybdenum may be used.

The second insulating layer 116a may be positioned on the source 115a and the drain 115b. The second insulating layer 116a may be a silicon oxide film SiOx, a silicon nitride film SiNx, or a multilayer thereof, but is not limited thereto. The second insulating layer 116a may be a passivation layer.

One of the source 115a and the drain 115b may be positioned on the second insulating layer 116a and may be connected to a shield metal 118 to prevent interference between the source 115a and the drain 115b. .

The third insulating layer 116b may be positioned on the second insulating layer 116a to increase the flatness. The third insulating layer 116b may include an organic material such as polyimide.

The lower electrode 117 may be positioned on the third insulating layer 116b. The lower electrode 117 may be selected as a cathode. The lower electrode 117 selected as the cathode may be formed of a metal that is opaque and has low work function, such as aluminum (Al) or aluminum alloy.

The bank layer 120 exposing the lower electrode 117 may be positioned on the lower electrode 117. The bank layer 120 may include an organic material such as benzocyclobutene (BCB) resin, acrylic resin, or polyimide resin.

The buffer layer 121 may be disposed on the bank layer 120 to cover the bank layer 120 and to expose the lower electrode 117. The buffer layer 121 may include an inorganic material, such as a silicon oxide film (SiOx) or a silicon nitride film (SiNx).

As such, when the buffer layer 121 formed of the inorganic material is formed on the bank layer 120, the sub-pixel shrinks due to outgassing or the like from the bank layer 120 formed of the organic material. In addition, when the lower electrode 117 is formed of a material vulnerable to oxidation, such as aluminum, when the oxidation process for removing the oxide film is performed, the problem that the bank layer 120 is damaged by the oxidation process can be prevented.

The organic emission layer 122 may be positioned on the lower electrode 117 exposed through the buffer layer 121. The organic emission layer 122 may be formed to emit one of red, green, and blue colors according to the sub-pixel P. FIG.

The upper electrode 123 may be positioned on the organic emission layer 122. The upper electrode 123 may be made of a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), or znO doped Al 2 O 3 (AZO), but is not limited thereto.

Hereinafter, an organic light emitting diode including the organic light emitting layer 122 will be described in more detail with reference to FIG. 2.

As shown in FIG. 2, the organic light emitting diode includes a lower electrode 117, an electron injection layer 122e, an electron transport layer 122d, an emission layer 122c, a hole transport layer 122b, a hole injection layer 122a, and an upper portion. It may include an electrode 123.

The electron injection layer 121e serves to facilitate the injection of electrons, and may be Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq or SAlq, but is not limited thereto.

The electron transport layer 121d serves to facilitate the transport of electrons, and may be made of any one or more selected from the group consisting of Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq, and SAlq. However, the present invention is not limited thereto.

The emission layer 121c may include a material emitting red, green, blue, and white light, and may be formed using phosphorescent or fluorescent materials.

When the light emitting layer 121c is red, the host material includes CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl), and includes PIQIr (acac) (bis (1-phenylisoquinoline) acetylacetonate Phosphorescent light containing a dopant including any one or more selected from the group consisting of iridium), PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (tris (1-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) It may be made of a material, alternatively may be made of a fluorescent material including PBD: Eu (DBM) 3 (Phen) or perylene, but is not limited thereto.

When the light emitting layer 121c is green, the light emitting layer 121c may include a host material including CBP or mCP, and may be made of a phosphor including a dopant material including Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium). Alternatively, the composition may be made of a fluorescent material including Alq3 (tris (8-hydroxyquinolino) aluminum), but is not limited thereto.

When the light emitting layer 121c is blue, the light emitting layer 121c may include a host material including CBP or mCP, and may be made of a phosphor including a dopant material including (4,6-F2ppy) 2Irpic. Alternatively, it may be made of a fluorescent material including any one selected from the group consisting of spiro-DPVBi, spiro-6P, distilbenzene (DSB), distriarylene (DSA), PFO-based polymer and PPV-based polymer, but It is not limited.

The hole transport layer 121b serves to facilitate the transport of holes, NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis- (3-methylphenyl) -N , N'-bis- (phenyl) -benzidine), s-TAD and MTDATA (4,4 ', 4 "-Tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine) It may be made of one or more, but is not limited thereto.

The hole injection layer 121a may play a role of smoothly injecting holes. CuPc (cupper phthalocyanine), PEDOT (poly (3,4) -ethylenedioxythiophene), PANI (polyaniline), and NPD (N, N-dinaphthyl) -N, N'-diphenyl benzidine) may be composed of any one or more selected from the group consisting of, but is not limited thereto.

Here, the present invention is not limited to FIG. 2, and at least one of the electron injection layer 122e, the electron transport layer 122d, the hole transport layer 122b, and the hole injection layer 122a may be omitted.

In the organic electroluminescent display device according to the first embodiment of the present invention, the transistor is a batam gate type. In the organic light emitting display device according to the first exemplary embodiment, since the buffer layer 121 is positioned to cover all of the bank layers 120 formed of organic material, the sublayer shrinkage problem due to outgassing and the bank layer 120 during the oxide removal process are performed. ) Can solve the problem of damage.

Second Embodiment

3 is a schematic cross-sectional view of an organic light emitting display device according to a second exemplary embodiment of the present invention, and FIG. 4 is a schematic view of a hierarchical structure of an organic light emitting diode.

Referring to FIG. 3, the active layer 114 may be positioned on the buffer layer 111 formed on the substrate 110. In addition, the first insulating layer 113 may be positioned on the active layer 114. In addition, a gate 112 may be positioned on the first insulating layer 113. In addition, the second insulating layer 116a may be positioned on the gate 112. In addition, the source 115a and the drain 115b may be positioned on the second insulating layer 116a to contact the active layer 114. In addition, a third insulating layer 116b may be disposed on the source 115a and the drain 115b. In addition, a lower electrode 117 connected to the source 115a or the drain 115b and selected as an anode may be positioned on the third insulating layer 116b. In addition, a bank layer 120 formed of an organic material may be disposed on the lower electrode 117 to expose the lower electrode 117. In addition, a buffer layer 121 formed of an inorganic material may be disposed on the bank layer 120 to cover all of the bank layers 120 and expose the lower electrode 117. In addition, the organic emission layer 122 may be positioned on the lower electrode 117. In addition, an upper electrode 123 selected as a cathode may be positioned on the organic emission layer 122.

Meanwhile, an organic light emitting diode including the organic light emitting layer 122 will be described as follows.

As shown in FIG. 4, the organic light emitting diode is a lower electrode 117 selected as an anode, a hole injection layer 122a, a hole transport layer 122b, an emission layer 122c, an electron transport layer 122d, and an electron injection layer 121e. And an upper electrode 123 selected as a cathode.

Here, the present invention is not limited to FIG. 4, and at least one of the hole injection layer 122a, the hole transport layer 122b, the electron transport layer 122d, and the electron injection layer 122e may be omitted.

In the organic electroluminescent display device according to the second embodiment of the present invention, the transistor is a top gate type. In the organic light emitting display device according to the second exemplary embodiment, the buffer layer 121 may be positioned to cover all of the bank layers 120 formed of organic materials.

As such, when the buffer layer 121 formed of the inorganic material is formed on the bank layer 120, the sub-pixel shrinks due to outgassing or the like from the bank layer 120 formed of the organic material.

Hereinafter, a method of manufacturing an organic light emitting display device according to an embodiment of the present invention will be described with reference to FIG. 5.

5 is a flowchart illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention, and FIG. 6 is a view for explaining an oxidation process.

1, 3, and 5, in order to manufacture an organic light emitting display device according to an exemplary embodiment, a gate 112, a source 115a, and a drain 115b are disposed on a substrate 110. A transistor forming step S101 is performed.

The transistor formed by the transistor forming step S101 may be formed in one of a batam gate type shown in FIG. 1 or a top gate type shown in FIG. 3. As described above with reference to FIG. 1 or 3, the transistor includes a buffer layer 111, a first insulating layer 113, a second insulating layer 116a, a third insulating layer 116b, and a shield metal 118. It may include, but is not limited to.

Next, a step S102 of forming a lower electrode 117 connected to the source 115a or the drain 115b on the transistor is performed. The lower electrode 117 may be selected as a cathode or an anode.

Next, in operation S103, the bank layer 120 is formed to expose the lower electrode 117 on the lower electrode 117. The bank layer 120 may be formed of an organic material.

Next, the buffer layer 121 is formed to cover the bank layer 120 and expose the lower electrode 117 on the bank layer 120 (S104). The buffer layer 121 may be formed of an inorganic material.

As such, when the buffer layer 121 formed of the inorganic material is formed on the bank layer 120, the sub-pixel shrinks due to outgassing or the like from the bank layer 120 formed of the organic material.

Meanwhile, when the lower electrode 117 is selected as the cathode, an oxide film 117b may be formed on the lower electrode 117 as shown in FIG. 6. As described above, when the lower electrode 117 is a cathode, the step S105 of selectively removing the oxide film 117b formed on the surface of the lower electrode 117 may be selectively performed after forming the buffer layer 121 (S104). have.

In the oxide film removing step S105, when the lower electrode 117 is formed of a material vulnerable to oxidation, such as aluminum, sputter etching (S / E) is performed to remove the oxide film 117b positioned on the lower electrode 117. will be. When the oxide film is removed in this manner, the buffer layer 121 may prevent the bank layer 120 from being damaged by the oxidation process.

Next, forming an organic emission layer 122 on the lower electrode 117 (S106). The organic emission layer 122 may be formed of a phosphorescent or fluorescent material to emit red, green, and blue colors depending on the subpixels.

Next, forming an upper electrode 123 on the organic light emitting layer 122 (S108). The upper electrode 123 may be formed as an anode or a cathode according to the lower electrode 117.

As described above, each embodiment of the present invention forms a buffer layer covering all of the bank layers in order to solve the problem that the subpixels contract by the outgassing generated from the bank layer formed of the organic material to define the emission region of the subpixels. And there is an effect to provide an organic light emitting display device that can improve the reliability. In addition, according to the present invention, when the lower electrode is formed of a material that is oxidized, the buffer layer has an effect of acting as a protective film that can prevent the bank layer from being damaged when the oxide film located on the lower electrode is removed.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is represented by the claims to be described later rather than the detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a cross-sectional view of an organic light emitting display device according to a first embodiment of the present invention.

2 is an exemplary hierarchical structure of an organic light emitting diode.

3 is a schematic cross-sectional view of an organic light emitting display device according to a second embodiment of the present invention;

4 illustrates a hierarchical structure of an organic light emitting diode.

5 is a flowchart illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

6 is a view for explaining an oxidation process.

<Explanation of symbols on main parts of the drawings>

110: substrate 112: gate

113: first insulating film 114: active layer

115a: source 115b: drain

116a: second insulating film 116b: third insulating film

117: lower electrode 120: bank layer

121: buffer layer 122: organic light emitting layer

123: upper electrode

Claims (5)

A transistor located on the substrate and comprising a gate, a source and a drain; A lower electrode disposed on the transistor and connected to a source or a drain of the transistor; A bank layer on the lower electrode and exposing the lower electrode; A buffer layer covering the bank layer and exposing the lower electrode; An organic light emitting layer on the lower electrode; And An organic light emitting display device comprising an upper electrode on the organic light emitting layer. The method of claim 1, The buffer layer, An organic light emitting display device, characterized in that formed of an inorganic material. Forming a transistor comprising a gate, a source, and a drain on the substrate; Forming a bottom electrode connected to the source or drain on the transistor; Forming a bank layer on the lower electrode to expose the lower electrode; Forming a buffer layer on the bank layer to cover the bank layer and expose the lower electrode; Forming an organic emission layer on the lower electrode; And And forming an upper electrode on the organic light emitting layer. The method of claim 3, When the lower electrode is a cathode, And removing the oxide film formed on the surface of the lower electrode after the forming of the inorganic buffer layer. The method of claim 3, The buffer layer, A method of manufacturing an organic light emitting display device, characterized in that formed of an inorganic material.

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