KR101622645B1 - Method of Manufacturing of the Organic Light Emitting Display Device - Google Patents

Abstract

The present invention relates to a method of manufacturing an organic light emitting diode display capable of improving reliability, and a method of manufacturing an organic light emitting display according to the present invention is defined as an active region and a pad region, Forming a first planarizing film on an element substrate on which a pad is formed in a pad region; forming a color filter layer on the first planarizing film of the pixel; Forming a first planarization layer on the pad and patterning the overcoat layer to expose the first planarization layer on the pad and the pad; and removing the first planarization layer to form a drain electrode And performing a second etch process to expose the pad electrode of the pad, And forming an organic electroluminescent device electrically connected to the drain electrode on the device substrate of the active region.

OLED, color filter, overcoat layer, contact hole, electrode

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an organic light emitting display, and more particularly, to a method of manufacturing an organic light emitting display capable of improving reliability.

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. An organic light emitting display (OLED) for displaying an image by controlling the amount of light emitted from the organic light emitting layer by using a flat panel display capable of reducing weight and volume, which is a disadvantage of a cathode ray tube (CRT)

The organic light emitting display device is a self-light emitting device using a thin light emitting layer between electrodes and has an advantage that it can be made thin like a paper. The organic light emitting display has a structure in which a plurality of pixels composed of three color (R, G, B) sub-pixels are arranged in a matrix form, a substrate on which a cell driver array and an organic light emitting array are formed is encapsulated, Thereby displaying an image.

In order to express color in an organic light emitting display, an organic light emitting layer that emits light of red, green, and blue is used. Since each organic light emitting layer has a different lifetime, it is difficult to maintain color when driving for a long time. In recent years, a method has been proposed in which each pixel has the same organic light emitting layer and a color is implemented using a color filter layer.

An overcoat layer is used to compensate the step difference of each sub-pixel by the color filter layer in manufacturing such an OLED display device. The overcoat layer is formed in such a state that the drain electrode of the thin film transistor or the electrode of the pad portion is exposed.

However, when the etching process for exposing the drain electrode or the pad electrode of the thin film transistor is performed after forming the overcoat layer, the drain electrode of the thin film transistor or the electrode of the pad portion is damaged by the etchant as shown in FIGS. 1A and 1B Or a residual film of the overcoat layer exists on the electrode, so that the electrode is not exposed properly.

The remaining film of the overcoat layer causes peeling of the ITO formed on the electrode in the subsequent process as shown in Figs. 2A and 2B. Damage to the residual film or electrodes of the overcoat layer does not properly supply signals to the pixels, thereby deteriorating the reliability of the display device. Even if there is no great difficulty in the initial driving of the display apparatus, the reliability of the display apparatus is deteriorated in the long-term driving.

In addition, the out gas generated by the color filter layer is not completely blocked by the overcoat layer, deteriorating the devices, thereby lowering the reliability of the display device.

In order to solve the above problems, the present invention provides a method of manufacturing an organic light emitting display device capable of improving reliability.

A method of manufacturing an organic light emitting diode display according to a first embodiment of the present invention includes defining an active region and a pad region, forming a pixel and a thin film transistor in an active region, forming a first planarization Forming a color filter layer on the first planarizing film of the pixel; forming an overcoat layer on the entire surface of the element substrate on which the color filter layer is formed; and patterning the overcoat layer to form the thin film Performing a first etching process to expose the transistor and the first planarization film on the pad; and performing a second etching process to expose the drain electrode of the thin film transistor and the pad electrode of the pad by removing the first planarization film And an organic electroluminescent element electrically connected to the exposed drain electrode, And forming on the element substrate in the active region.

A method of manufacturing an organic light emitting diode display according to a second embodiment of the present invention includes defining an active region and a pad region, forming a pixel and a thin film transistor in an active region, forming a first planarization Forming a color filter layer on the first planarizing film of the pixel; forming an overcoat layer on the entire surface of the element substrate on which the color filter layer is formed; and patterning the overcoat layer Performing a first etch process to expose the first planarization film on the thin film transistor and the pad, forming a second planarization film on the patterned overcoat layer and the exposed first planarization film, The planarizing film and the second planarizing film are removed so that the drain electrode of the thin film transistor and the pad electrode of the pad are connected to the A second etching step of performing a process and the organic light emitting element is electrically connected to the drain electrode and exposure to a step formed on the element substrate in the active region.

The first etching process is a wet etching process, and the second etching process is a dry etching process.

A first contact hole through which the first planarization film on the thin film transistor is exposed is formed through the first etching process and a second contact hole through which the drain electrode of the thin film transistor is exposed is formed through the second etching process , And the size of the lower hole of the first contact hole coincides with the size of the upper hole of the second contact hole.

The first etching process is performed using KOH and TMAH (TetraMethlymmonium Hydroxid).

The organic electroluminescent device includes a first electrode electrically connected to the drain electrode, a second electrode opposing the first electrode, and an organic emission layer formed between the first electrode and the second electrode to emit light And the organic light emitting layer emits red, green, blue or white light.

The present invention can prevent the electrode from being damaged by the etchant or prevent the residual layer of the overcoat layer from being present on the electrode, since the etch process for exposing the electrode after forming the overcoat layer is performed.

In addition, by completely exposing the electrodes, signals can be properly supplied to the pixels, thereby improving the reliability of the display device.

In addition, the present invention further includes a flattening film for blocking the outgassing by the color filter layer, thereby preventing deterioration of the devices due to outgas, thereby improving the reliability of the display device.

Hereinafter, a method for fabricating an OLED display device according to the present invention will be described in detail with reference to the accompanying drawings.

The element substrate of the present invention is defined as an active region and a pad region, and a pixel, a thin film transistor, and a capacitor are formed in the active region, and a pad is formed in the pad region. 3A to 3G are cross-sectional views illustrating a method of manufacturing an OLED display according to a first embodiment of the present invention.

3A, a planarization layer 152 is formed on an element substrate 110 on which a thin film transistor (Tr) 182, a capacitor (Cst) 184, and a pad (Pad) 186 are formed.

As the element substrate 110, an insulating glass, a plastic, or a conductive substrate can be used.

The thin film transistor 182 is a top-gate type and includes a semiconductor layer 114 having an impurity-doped source / drain region and a channel region formed on the buffer layer 112, And a gate insulating film 116. The thin film transistor Tr has a gate electrode 122 overlapping over the channel region of the semiconductor layer 114 on the gate insulating film, an interlayer insulating film 118 formed on the entire surface including the gate electrode 122, 118 and drain electrode 126 and source electrode 127, respectively, which are in contact with the drain / source region, to control turn-on or turn-off of the voltage within the pixel.

The capacitor 184 includes a lower electrode 115 doped with impurities formed on the buffer layer 112 and a gate insulating film 116 formed on the entire surface including the lower electrode 115 and an interlayer insulating film 118 A first upper electrode 123 and a second upper electrode 128 formed between the first upper electrode 123 and the second upper electrode 128 to keep the gate voltage of the thin film transistor 182 constant.

The pads 186 are each formed by extending in a gate wiring (not shown) or a data wiring (not shown) to supply an external signal to a pixel. The pad 186 is formed on the device substrate 110 by sequentially stacking the buffer layer 112 and the gate insulating film 116 and the lower pad electrode 124 and the lower pad electrode 124 exposed by the interlayer insulating film 118. [ And an upper pad electrode 129 electrically connected to the pad electrode 124.

The buffer layer 112 is formed of an insulating material such as a silicon nitride film or a silicon oxide film on the element substrate 110 and prevents impurities from the element substrate 110 from penetrating into the transistor Tr in a subsequent process .

The semiconductor layer 114 of the thin film transistor 182 and the lower electrode 115 of the capacitor 184 may be an amorphous silicon film or a polycrystalline silicon film crystallized therefrom. As the gate insulating film 116, an inorganic insulating material such as a silicon nitride film (SiNx) or a silicon oxide film (SiOx) is used and may be a single layer or multiple layers thereof.

The gate electrode 122 of the thin film transistor 182, the first upper electrode 123 of the capacitor 184 and the lower pad electrode 124 of the pad 186 are formed by photolithography and etching using metal, Can be simultaneously formed. At this time, chromium (Cr), copper (Cu), titanium (Ti), tantalum (Ta), molybdenum (Mo), aluminum metal and the like are used as a single layer or multilayer structure.

The interlayer insulating film 118 is formed by a deposition method such as CVD (Chemical Vapor Deposition), and may be a silicon oxide film, a silicon nitride film, or a multilayer thereof. The interlayer insulating film 118 exposes the source / drain electrodes 126 and 127 of the thin film transistor Tr and the upper pad electrode 129 of the pad 186.

The source electrode 127 and the drain electrode 126 of the thin film transistor 182 and the second upper electrode 128 of the capacitor 184 and the upper pad electrode 129 of the pad 186 are formed by a deposition method such as sputtering And then patterned by a photolithography process and an etching process. The source electrode 127 and the drain electrode 126 of the thin film transistor 182 and the second upper electrode 128 of the capacitor 184 and the upper pad electrode 129 of the pad 186 can be formed at the same time.

The source electrode 127 and the drain electrode 126 of the thin film transistor 182 and the second upper electrode 128 of the capacitor 184 and the upper pad electrode 129 of the pad 186 are made of copper , Aluminum (Al), an aluminum alloy (AlNd), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum-tungsten .

The source electrode 127 and the drain electrode 126 of the thin film transistor 182 are connected to the semiconductor layer 114 through the interlayer insulating film 118 exposing the semiconductor layer 114, (129) is electrically connected to the lower pad electrode (124).

The planarizing film 152 is formed on the entire surface of the element substrate 110 including the thin film transistor 182, the capacitor 184 and the pad 186 by using an inorganic insulating material or an organic insulating material such as BCB (Benzocyclobutene), acrylic resin, PFCB And then applying an insulating material by a method such as spin coating.

3B, a color filter layer 154 is formed on the planarization layer 152 of the pixel region on the side of the thin film transistor 182 and the element substrate 110 on which the color filter layer 154 and the pads 186 are formed, An overcoat layer 156 is formed on the entire surface.

The color filter layer 154 may be formed of color filter layers of red (R), green (G), blue (B), and white (W) The overcoat layer 156 is formed by using a transparent resin such as an acrylic epoxy having an insulating property for compensating a step according to the formation of the color filter layer 154. [

Referring to FIG. 3C, the first etching process is performed to pattern the overcoat layer 156 on the thin film transistor 182 to form the first contact hole 162 partially exposing the planarization layer 152, The overcoat layer 156 on the overcoat layer 186 is completely removed to expose the planarization layer 152. The first etching process is performed using a KOH solution and TMAH as a wet etching process.

At this time, by etching the overcoat layer 156 to only the upper surface of the planarization film 152, the drain electrode 126 of the thin film transistor 182 formed at the bottom from the etchant used in the first etching process, It is possible to prevent the pad electrode 129 from being damaged.

Referring to FIG. 3D, a second contact hole 164 exposing the drain electrode 126 of the thin film transistor 182 and a second contact hole 164 exposing the upper pad electrode 129 of the pad 186 are formed by performing a second etching process. 3 contact holes 166 are formed. The second contact hole 164 and the third contact hole 166 are formed through the planarization film 152. The second etching process is performed by a dry etching process.

At this time, the second contact hole 164 is connected to the first contact hole 162 without a step. That is, the lower hole size of the first contact hole 162 corresponds to the upper hole size of the second contact hole 164.

Since the first and second etching processes are performed to expose the drain electrode 126 of the thin film transistor 182 and the upper pad electrode 129 of the pad 186, It is possible to prevent the remaining film of the overcoat layer 156 from remaining on the overcoat layer 156. Therefore, the present invention can improve the reliability of the display device by properly supplying the signals to the pixels by completely exposing the electrodes without damaging them.

Then, an organic electroluminescent element is formed on the thin film transistor 182. [

3E, a conductive material is deposited on the element substrate 110, a first electrode 132 electrically connected to the drain electrode 126 of the thin film transistor 182 is formed by a photoetching technique, (132a) electrically connected to the upper pad electrode (129) of the pad electrode (186).

The first electrode 132 extends to the pixel region as an anode and is electrically connected to the drain electrode 126 of the thin film transistor 182 through the second contact hole 164. The oxidation preventing film 132a is electrically connected to the upper pad electrode 129 of the pad 186 through the third contact hole 166. [

The first electrode 132 and the oxidation preventing film 132a are formed by depositing ITO (Indium Tin Oxide), TO (Tin Oxide), IZO (Indium Zinc Oxide) or ITZO by a deposition method such as sputtering, Respectively.

3F, an insulating layer is deposited on the element substrate 110 on which the first electrode 132 is formed and is patterned by a photoetching process so that the bank insulating layer 134, in which the first electrode 132 is exposed, .

Referring to FIG. 3G, the organic light emitting layer 136 and the second electrode 138 are formed on the element substrate 110 of the active region except for the region where the pads are formed, thereby manufacturing the organic electroluminescent device 188.

The organic light emitting layer 136 is a layer in which an exciton formed by the combination of holes and electrons injected from the first electrode 132 and the second electrode 138 falls to a ground state and emits light. The organic light emitting layer 136 is separated by a common layer formed on the entire surface of the active region of the element substrate 110 and the bank insulating layer 134. The organic light emitting layer 136 emits red (R), green (G) ) Or white (W) color light.

The second electrode 138 is formed in at least one layer structure using a transparent conductive material or an opaque conductive material on the entire surface of the active region of the element substrate 110 on which the organic light emitting layer 136 is formed, .

When a signal is applied through a gate line (not shown) of the organic light emitting diode display as described above, a switching thin film transistor (not shown) is turned on and a signal of a data line (not shown) 182, and the driving thin film transistor 182 is turned on, so that light is emitted through the organic electroluminescent device 188.

At this time, the capacitor 184 maintains the gate voltage of the driving thin film transistor 182 constant when the switching thin film transistor (not shown) is turned off.

Hereinafter, a method of manufacturing an OLED display according to a second embodiment of the present invention will be described with reference to FIGS. 4A to 4G.

4A, a first planarization layer 252 is formed on an element substrate 210 on which a thin film transistor (Tr) 282, a capacitor (Cst) 284 and a pad 286 are formed, The overcoat layer 256 is entirely formed on the element substrate 210.

The semiconductor layer 214, the gate insulating film 216, the gate electrode 222, the interlayer insulating film 218, the drain electrode 126, and the source electrode 212, the thin film transistor 282, the buffer layer 212, The second upper electrode 228, the color filter layer 254 and the overcoat layer 256 and the lower pad electrode (not shown) of the pad region are formed on the upper electrode 227, the capacitor 284, the lower electrode 215, the first upper electrode 223, 224 and the pad 286 including the upper pad electrode 229 are the same as those according to the first embodiment of the present invention, and thus description thereof will be omitted.

Referring to FIG. 4B, the first etching process is performed to pattern the overcoat layer 256 on the thin film transistor 282 to form a first contact hole 262 partially exposing the first planarization film 252. The first etching process is performed using a KOH solution and TMAH as a wet etching process.

At this time, only the upper surface of the first planarization layer 252 is etched to form the overcoat layer 256, so that the drain electrode 226 of the thin film transistor 282 formed at the bottom from the etchant used in the first etching process, It is possible to prevent the electrode (not shown) from being damaged.

Referring to FIG. 4C, a second planarization layer 258 is formed on the entire surface of the element substrate 210 on which a part of the first planarization layer 252 is exposed. The second planarization layer 258 may be formed by applying an inorganic insulating material or an organic insulating material such as BCB (Benzocyclobutene), acrylic resin, PFCB, etc. by a method such as spin coating.

The second planarization layer 258 completely blocks out-gas by the color filter layer 254 to prevent deterioration of devices such as a thin film transistor, thereby improving the reliability of the display device. The second planarization film 258 may not be formed on the pad 286. [

Referring to FIG. 4D, a second contact hole 264 exposing the drain electrode 226 of the thin film transistor 282 by performing a second etching process, and a third contact hole 262 exposing the pad electrode of the pad region (Not shown). A second contact hole 264 and a third contact hole (not shown) are formed through the first planarization film 252 and the second planarization film 258. The second etching process is performed by a dry etching process.

As described above, the present invention performs the first etching process and the second etching process to expose the drain electrode 226 and the pad electrode of the thin film transistor 282, thereby preventing the remaining layer of the overcoat layer 256 from being left on the electrodes . Therefore, the present invention can improve the reliability of the display device by properly supplying the signals to the pixels by completely exposing the electrodes without damaging them.

4E to 4G, an organic electroluminescent element 288 is formed on the thin film transistor 282. Next,

The structure of the first electrode 232, the bank insulating film 234, the organic light emitting layer 236 and the second electrode 238 constituting the organic electroluminescent element 288 is the same as that of the first embodiment of the present invention, The description of which will be omitted.

As described above, according to the method of manufacturing an organic light emitting diode display according to the present invention, since the electrode is exposed through two etching processes without performing batch etching, it is possible to completely expose the electrode without a remainder, Thereby improving the reliability of the display device.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

FIGS. 1A and 1B are SEM photographs showing electrodes of a conventional organic light emitting diode display fabricated according to a method of manufacturing an organic light emitting display device, which are damaged or remained by an etchant.

FIGS. 2A and 2B are SEM photographs illustrating the phenomenon that the electrodes of the OLED display manufactured according to the conventional method of manufacturing an organic light emitting display are peeled off.

3A to 3G are cross-sectional views illustrating a method of manufacturing an OLED display according to a first embodiment of the present invention.

4A to 4G are cross-sectional views illustrating a method of manufacturing an OLED display according to a second embodiment of the present invention.

5 is an exposed photograph of an electrode of an organic light emitting display manufactured according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

110, 210: element substrate 126, 226: drain electrode

129: upper pad electrode 132, 232: first electrode

152: planarizing film 156, 256: overcoat layer

182, 282: thin film transistors 184, 284: capacitors

186, 286: pads 188, 288: organic electroluminescent element

252: first flattening film 258: second flattening film

Claims (10)

Forming a first planarization film on an element substrate defined as an active region and a pad region, in which a pixel and a thin film transistor are formed in an active region, and a pad is formed in the pad region; Forming a color filter layer on the first planarization film of the pixel; Forming an overcoat layer on the entire surface of the element substrate on which the color filter layer is formed; Performing a first etch process to pattern the overcoat layer to expose the first planarization layer on the thin film transistor and the pad; Performing a second etching process such that the drain electrode of the thin film transistor and the pad electrode of the pad are exposed by removing the first planarization film; And And forming an organic electroluminescent device electrically connected to the exposed drain electrode on the device substrate of the active region. The method of claim 1, wherein the first etching process is a wet etching process, Wherein the second etching process is a dry etching process. 2. The method of claim 1, wherein the first contact hole is formed through the first etching process to expose the first planarization film on the thin film transistor, A second contact hole through which the drain electrode of the thin film transistor is exposed is formed through the second etching process, And the size of the lower hole of the first contact hole is equal to the size of the upper hole of the second contact hole. The method of claim 1, wherein the first etching process is performed using KOH and TMAH. The organic electroluminescent device of claim 1, wherein the organic electroluminescent device includes a first electrode electrically connected to the drain electrode, a second electrode opposing the first electrode, and a second electrode formed between the first electrode and the second electrode, An organic light emitting layer for emitting light, Wherein the organic light emitting layer emits red, green, blue or white light. Forming a first planarization film on an element substrate defined as an active region and a pad region, in which a pixel and a thin film transistor are formed in an active region, and a pad is formed in the pad region; Forming a color filter layer on the first planarization film of the pixel; Forming an overcoat layer on the entire surface of the element substrate on which the color filter layer is formed; Performing a first etch process to pattern the overcoat layer to expose the first planarization layer on the thin film transistor and the pad; Forming a second planarization film on the patterned overcoat layer and the exposed first planarization film; Removing the first planarization film and the second planarization film to perform a second etching process so that a drain electrode of the thin film transistor and a pad electrode of the pad are exposed; And And forming an organic electroluminescent device electrically connected to the exposed drain electrode on the device substrate of the active region. 7. The method of claim 6, wherein the first etching process is a wet etching process, Wherein the second etching process is a dry etching process. The method as claimed in claim 6, wherein the first contact hole is formed through the first etching process to expose the first planarizing film on the thin film transistor, A second contact hole through which the drain electrode of the thin film transistor is exposed is formed through the second etching process, And the size of the lower hole of the first contact hole is equal to the size of the upper hole of the second contact hole. 7. The method according to claim 6, wherein the first etching process is performed using KOH and TMAH. 7. The organic electroluminescent device of claim 6, wherein the organic electroluminescent device includes a first electrode electrically connected to the drain electrode, a second electrode opposing the first electrode, and a second electrode formed between the first electrode and the second electrode, An organic light emitting layer for emitting light, Wherein the organic light emitting layer emits red, green, blue or white light.

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