KR100739574B1 - OLED display and manufacturing method thereof - Google Patents

Abstract

An organic light emitting display having reduced IR drop and a method of manufacturing the same are provided. The organic light emitting diode display according to the exemplary embodiment of the present invention uses a common power supply line electrically connected to a second TFT used as a driving TFT, using ITO / Ag / ITO containing the same material as the first electrode of the light emitting device, for example, Ag. It is formed on top of the planarization film. According to this configuration, by forming the common power supply line with the same material as the first electrode, the IR drop of the common power supply line can be reduced.

OLED, organic light emitting, common power wiring, luminance, resistivity, anode,

Description

Organic light emitting display and manufacturing method thereof {ORGANIC LIGHT EMITTING DISPLAY AND METHOD FOR FABRICATING THEREOF}

1 to 5 are perspective views schematically illustrating main parts of a structure of a method of manufacturing an organic light emitting diode display according to an exemplary embodiment of the present invention.

FIG. 6 is a "VI-VI" cross-sectional view illustrating a state in which a light emitting device is formed on the driving circuit board of FIG. 5.

FIG. 7 is a cross-sectional view of "VIII-VIII" showing a state in which a light emitting element is formed on the driving circuit board of FIG. 5.

8 and 9 are perspective views schematically illustrating main parts of a structure of a method of manufacturing an organic light emitting diode display according to another exemplary embodiment of the present invention.

FIG. 10 is a cross-sectional view of "VIII-VIII" showing a state where a light emitting element is formed on the driving circuit board of FIG.

FIG. 11 is a sectional view taken along the line "XI-XI" showing a state where a light emitting element is formed on the driving circuit board of FIG.

The present invention relates to an organic light emitting display and a method of manufacturing the same, and more particularly, to an organic light emitting display and a method of manufacturing the same that can prevent the degradation of the image quality due to IR drop (drop).

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP) and Organic Light Emitting Display (PDP). Etc.

The organic light emitting diode display is a self-luminous display device that electrically excites an organic compound to emit light. The organic light emitting diode display may display an image by voltage driving or current driving N × M organic light emitting devices.

The organic light emitting diode has a diode characteristic and is also called an organic light emitting diode, which is composed of an anode electrode as a hole injection electrode, an organic thin film as a light emitting layer, and a cathode electrode as an electron injection electrode. Holes and electrons are injected into the organic thin film to emit light when an exciton in which holes and electrons are combined falls from an excited state to a ground state.

In general, the organic light emitting diode display includes a driving circuit board on which a driving circuit unit is formed. A buffer film is provided on the driving circuit board, and a driving circuit part including a plurality of thin film transistors (hereinafter, referred to as TFTs) is formed on the buffer film.

The driving circuit unit includes at least two TFTs for each of three (red, green, blue) sub pixels constituting one organic light emitting cell.

The first TFT, which is one of the two TFTs, is a switching TFT that selects an element to emit light from among a plurality of organic light emitting cells, and the first gate electrode of the first TFT is electrically connected to the scan line, The electrode is electrically connected to the data line arranged to be orthogonal to the scan line, and the drain electrode is electrically connected to the drain region of the first semiconductor layer and the lower electrode for the capacitor.

The second TFT, which is the other one of the two TFTs, is a driving TFT for applying a driving power for emitting the light emitting layer of the selected organic light emitting cell, and the second gate electrode of the second TFT is electrically connected to the lower electrode for the capacitor. The source electrode is electrically connected to the common power line.

In the case of the driver circuit section including six TFTs, the second TFT may be an emission control emission TFT.

Therefore, the process of forming the driving circuit unit and the light emitting devices in the sub-pixel region will be briefly described as follows.

In order to form a driving circuit, a buffer film is formed on one surface of the driving circuit board, and then first and second semiconductor layers are formed in the first TFT region and the second TFT region, respectively, on the buffer film.

Here, the first and second semiconductor layers refer to layers, for example, polysilicon, on which source and drain regions and channel regions are formed, respectively. The first and second semiconductor layers are each formed in a sub pixel area. Therefore, semiconductor layers corresponding to twice the subpixels are formed in the display area of the driving circuit board.

Subsequently, a gate insulating film is formed over the first and second semiconductor layers and the buffer film, and first and second gate electrodes are formed over the gate insulating film of each TFT region, respectively. At this time, the scan line connected to the first gate electrode of the first TFT and the lower electrode for the capacitor connected to the gate electrode of the second TFT are also simultaneously formed.

Subsequently, an interlayer insulating film having a plurality of via holes is formed on the structure described above, and the source electrode and the drain electrode of the first TFT, the source electrode and the drain electrode of the second TFT, and the source electrode of the first TFT are electrically formed on the interlayer insulating film. And a common power line electrically connected to the data line connected to the first and second source electrodes of the second TFT.

At this time, the drain electrode of the first TFT is also electrically connected to the lower electrode of the capacitor.

Thereafter, a planarization film is formed on the structure, and then a light emitting device is formed on the planarization film.

The light emitting device includes a pixel electrode consisting of first and second electrodes, and an emitting layer EML disposed between the first and second electrodes.

Specifically, the pixel electrode includes an anode electrode which is a hole injection electrode and a cathode electrode which is an electron injection electrode. In a conventional light emitting device, a lower first electrode serves as an anode electrode and an upper second electrode serves as a cathode electrode. The lower first electrode is electrically connected to the drain electrode of the second TFT.

The light emitting layer has a multilayer structure including an electron transport layer (ETL) and a hole transport layer (HTL), and includes an electron injection layer (EIL) and a hole injection layer. ; HIL) may be further included.

In the organic light emitting display having the above structure, the source electrode and the drain electrode of the first TFT, the source electrode and the drain electrode of the second TFT, the data line and the second TFT electrically connected to the source electrode of the first TFT The common power line electrically connected to the source electrode is typically made of Ti / Al / Ti.

However, since Al has a specific resistance of 2.2 × 10 ⁻⁶ Ω · cm, a common power line including Al will exhibit a relatively large resistance value.

Therefore, when an IR drop is generated along a common power line, problems of luminance unevenness and crosstalk are caused by the IR drop, and this problem occurs as the area of the organic light emitting diode display becomes larger.

The present invention has been made to solve the above problems, and an object thereof is to provide an organic light emitting display device having reduced IR drop.

Another object of the present invention is to provide a manufacturing method capable of effectively manufacturing the above organic light emitting display device.

The present invention to achieve the above object,

A common power supply line electrically connected to a second TFT used as a driving TFT is achieved by an organic light emitting display device in which a common power line is formed on the same layer of the same material as a first electrode, for example, an anode, of a light emitting element disposed above the planarization film. Can be.

According to this configuration, when the anode electrode is formed of an electrode material containing Ag, such as ITO / Ag / ITO, the common power supply line is also formed at the same time, thereby reducing the IR drop of the common power supply line.

According to an embodiment of the present invention, the common power line formed on the planarization film includes a source electrode portion for a second TFT that is directly connected to a source region of the second TFT through a via. The first electrode includes a drain electrode part for a second TFT directly connected to a drain region of the second TFT through a via.

In the organic light emitting display having the above-described configuration, the data line electrically connected to the first TFT may be formed on the same layer, for example, the planarization layer, of the same material as the first electrode, similarly to the common power line.

In this case, the data line has a first source electrode portion electrically connected to the source region of the first TFT via vias, and the drain region of the first TFT is electrically connected to the connecting electrode via vias.

The connection electrode is made of the same material as the first and second gate electrodes, and is electrically connected to the lower electrode for a capacitor formed on the same layer, for example, an upper portion of the gate insulating layer.

In addition, an upper electrode for a capacitor is provided on the interlayer insulating layer covering the lower electrode, and the electrode is electrically connected through a common power line and a via provided on the planarization layer.

As another example, the data line may be formed on the interlayer insulating layer.

In this case, the data line is integrally formed with the source electrode of the first TFT, and a drain electrode made of the same material as the data line is electrically connected to the drain region of the first TFT.

The drain electrode is electrically connected to the lower electrode for the capacitor formed on the gate insulating layer through the via, and the upper electrode for the capacitor formed to the upper portion of the interlayer insulating film is electrically connected through the common power line and the via provided on the planarization layer. do.

The organic light emitting diode display having the above-described structure is made of an electrode forming material including Ag in common power line, thereby reducing IR drop.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the following embodiments, when a part such as a layer, a film, or the like is formed at the "top" of another part, it is not only when it is "just above" the other part but also when there is another part in the middle. Include.

In the following embodiment, a driving circuit portion having a 2Tr-1Cap structure consisting of two TFTs and one capacitor is described as an example, but the present invention is not limited by the structure of the driving circuit portion, and the driving circuit portion is a product. It can be modified in various forms according to.

1 to 5 are perspective views schematically showing the main components of the organic light emitting display device according to an embodiment of the present invention, and FIG. 6 is a cross-sectional view "VI-VI" of FIG. 5, and FIG. 7. Is a cross-sectional view of FIG. 5. 6 and 7 assume that a light emitting device is formed on the driving circuit board of FIG. 5.

The organic light emitting diode display according to the exemplary embodiment of the present invention includes a driving circuit board 10. As the driving circuit board 10, a glass substrate made of a transparent material or a resin substrate made of an opaque material may be used, and a thin metal substrate capable of bending may be used.

For the sake of simplicity, FIGS. 1 to 5 only show a driving circuit board of a region in which a driving circuit unit is formed among one sub pixel region.

An embodiment of the present invention will be described with reference to this. As shown in FIG. 1, the buffer film 20 is formed on the driving circuit board 10, and the first TFT region and the second TFT on the buffer film 20 are formed. The first semiconductor layer 110 and the second semiconductor layer 210 are formed in the TFT region, respectively.

Here, the first and second semiconductor layers 110 and 210 refer to polysilicon including source regions 112 and 212, drain regions 114 and 214, and channel regions 116 and 216, respectively.

Subsequently, as shown in FIG. 2, the gate insulating film 22 is formed, and the first gate electrode 120 and the scan line 310 and the second gate electrode are integrally formed on the gate insulating film 22. And a lower electrode 322 for the capacitor 320 formed integrally with the electrode.

3 and 4, an interlayer insulating film 24 is formed, and a data line 330 made of Ti / Al / Ti and a source electrode of the first TFT (above the interlayer insulating film 24). 130, a drain electrode 140, and an upper electrode 324 for the capacitor 320 are formed, respectively.

The data line 330 is provided in a direction orthogonal to the scan line 310, the data line 330 is integrally formed with the source electrode 130, and the source electrode 130 is formed through the via 132. It is electrically connected to the source region 112.

The drain electrode 140 is electrically connected to the drain region 114 through the via 142, and is electrically connected to the lower electrode 322 for the capacitor 320 through another via 144.

Subsequently, as shown in FIG. 5, the planarization film 26 is formed, and the common power supply line 340 and the first electrode 410 are formed on the planarization film 26. Here, the first electrode 410 is an anode electrode as a hole injection electrode.

At this time, the common power line 340 and the first electrode 410 is formed of a multi-layer structure of a material containing Ag, preferably ITO / Ag / ITO.

The common power line 340 is formed at a position facing the data line 330 in a direction orthogonal to the scan line 310. The common power supply line 340 has a shape having a second source electrode portion 342, and the second source electrode portion 342 forms a source region 212 and a via 344 of the second TFT. Electrically connected via In addition, the common power line 340 is electrically connected to the lower upper electrode 324 through the via 346.

The first electrode 410 is formed in a shape having a second drain electrode portion 412, and the second drain electrode portion 412 forms the drain region 214 and the via 414 of the second TFT. Electrically connected via

Thereafter, the pixel defining layer 440 is formed to expose the first electrode 410, and the light emitting layer 420 and the second electrode 430 are formed on the first electrode 410 to form the pixel portion 400. do. Here, the second electrode 430 is a cathode electrode as the electron injection electrode.

After all the structures of the driving circuit board 10 are formed according to the above-described process, encapsulation is performed by using an encap glass or metal cap (not shown) or forming a thin film for encapsulation.

In this embodiment, the common power supply line 340 is formed of the same material as the first electrode 410 including Ag, for example, ITO / Ag / ITO. However, since the Ag has a specific resistance of 1.62 × 10 ⁻⁶ Ω · cm, the Ag has a lower specific resistance than that of Al which has conventionally constituted the common power supply line 340.

Therefore, the common power line 340 made of an electrode forming material including Ag can reduce the IR drop as compared with the case containing the material containing Al, thereby reducing unnecessary voltage and reducing power consumption. Can suppress the vertical crosstalk and improve the image quality.

8 and 9 are perspective views schematically illustrating a main part configuration to illustrate a method of manufacturing an organic light emitting diode display according to another exemplary embodiment. FIG. 10 is a cross-sectional view taken along line “VII-VII” of FIG. 9. 9 is a cross-sectional view taken along line "XI-XI" of FIG. 9. 10 and 11 assume that a light emitting device is formed on the driving circuit board of FIG. 9.

In the manufacturing of the organic light emitting diode display of the present embodiment, the process of forming the interlayer insulating film 24 is the same as in the above-described embodiment, and a description thereof will be omitted.

As shown in Fig. 8, after the interlayer insulating film 24 is formed, an upper electrode 324 for capacitors is formed on the film 24.

Subsequently, as shown in FIG. 9, the planarization film 26 is formed, and the data line 330, the connection electrode 350, and the common electrode having a multi-layer structure of an electrode forming material containing Ag, such as ITO / Ag / ITO, are common. The power line 340 and the first electrode 410 are formed on the planarization layer 26, respectively.

The data line 330 is formed in a shape having a first source electrode 332. The first source electrode 332 is electrically formed through the source region 112 and the via 334 of the first TFT. Connect with

The connection electrode 350 is electrically connected to the drain region 114 of the first TFT through the via 352, and is electrically connected to the lower electrode 322 for the capacitor through another via 354.

The common power line 340 has a shape having a second source electrode portion 342, and the second source electrode portion 342 has a source region 212 and a via 344 of the second TFT. Electrically connected via In addition, the common power line 340 is electrically connected to the upper electrode 324 for the capacitor 320 under the via 346.

Meanwhile, the first electrode 410 is formed in a shape having the second drain electrode portion 412, and the second drain electrode portion 412 is formed through the drain region 214 and the via 414 of the second TFT. Connect electrically.

Thereafter, the pixel defining layer 440 is formed to expose the first electrode 410, and the light emitting layer 420 and the second electrode 430 are formed on the first electrode 410 to form the light emitting device 400. do. The second electrode 430 is a cathode electrode as an electron injection electrode, and the first electrode 410 is an anode electrode as a hole injection electrode. Of course, the first electrode and the second electrode may be interchanged according to product specifications.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, the organic light emitting diode display according to the exemplary embodiment of the present invention forms a common power line with a material having a lower resistivity than Al, such as an anode electrode forming material including Ag, thereby reducing IR drop. .

Therefore, unnecessary voltage can be reduced, power consumption can be reduced, and vertical crosstalk can be suppressed to improve image quality.

Claims (22)

A driving circuit unit including a first TFT and a second TFT respectively disposed in a sub pixel area of the driving circuit board; A light emitting device including a first electrode disposed below the second electrode, a second electrode disposed above the electrode, and a light emitting layer disposed between the electrodes, the light emitting device disposed on the driving circuit unit; And Common power line formed on the same layer with the same material as the first electrode Including; The common power line includes a source electrode portion for a second TFT directly connected to a source region of the second TFT through a via, and the first electrode is directly connected to a drain region of the second TFT through a via. An organic light emitting display device having a drain electrode portion for a TFT. The method of claim 1, The organic light emitting display device of claim 1, wherein the first electrode comprises an anode electrode. The method of claim 2, The anode electrode includes Ag. The method of claim 3, wherein And the anode electrode is made of ITO / Ag / ITO. The method according to any one of claims 1 to 4, The second TFT includes a second semiconductor layer forming a source region, a drain region, and a channel region, and a second gate electrode formed on the second semiconductor layer with a gate insulating layer interposed therebetween. The method of claim 5, The first TFT includes a first semiconductor layer forming a source region, a drain region, and a channel region, and a first gate electrode formed on the first semiconductor layer with the gate insulating layer interposed therebetween. . The method of claim 6, A lower electrode for a capacitor formed of the same material as the first and second gate electrodes and electrically connected to the second gate electrode, and provided with the first and second gate electrodes and the lower electrode; An interlayer insulating film is provided over the gate insulating film, and an upper electrode for a capacitor is provided over the interlayer insulating film. The method of claim 7, wherein A planarization layer is provided on the upper electrode and the interlayer insulating layer, and a first electrode, a common power line, a data line, and a connection electrode formed of the same material are provided on the planarization layer, and the data line is connected to the first through a via. And a source electrode portion for a first TFT directly connected to a source region of a TFT, wherein the connection electrode electrically connects the drain region for the first TFT and a lower electrode through vias. The method of claim 7, wherein A source electrode electrically connected to the source region of the first TFT, a data line electrically connected to the electrode, and a drain electrode electrically connected to the drain region and the lower electrode of the first TFT are disposed on the interlayer insulating layer. Further provided organic light emitting display device. The method of claim 9, A planarization layer is provided on a source electrode and a drain electrode, a data line, an upper electrode, and an interlayer insulating layer of the first TFT, and the first electrode and a common power line are provided on the planarization layer, and the common power line is connected to the upper portion through a via. An organic light emitting display device connected directly to an electrode. A drive circuit board; A first semiconductor layer of a first TFT and a second semiconductor layer of a second TFT having a source region, a drain region, and a channel region, and disposed in a sub pixel region of a driving circuit board; A gate insulating layer formed on the first and second semiconductor layers; A first gate electrode of a first TFT and a second gate electrode of a second TFT formed on the gate insulating layer, and a scan line electrically connected to the first gate electrode; An interlayer insulating layer formed on the first and second gate electrodes, the scan line, and the gate insulating layer; A planarization film disposed on the interlayer insulating film; A first electrode having a drain electrode portion for a second TFT electrically connected to a drain region of the second TFT through a via, a light emitting layer provided on the first electrode, and a second electrode provided on the light emitting layer A light emitting device provided on the planarization film; A common power line provided on the same layer of the same material as the first electrode and having a source electrode portion for a second TFT electrically connected to a source region of the second TFT; A data line provided on the same layer of the same material as the common power supply line, disposed to be orthogonal to the scan line, and provided with a source electrode portion for a first TFT electrically connected to a source region of the first TFT; And A connection electrode provided on the same layer of the same material as the data line and electrically connected to the drain region of the first TFT An organic light emitting display comprising a. The method of claim 11, The capacitor further comprises a lower electrode for a capacitor made of the same material as the second gate electrode and provided on an upper portion of the gate insulating layer, and an upper electrode for a capacitor provided between the interlayer insulating layer and the planarization layer. And an upper electrode electrically connected to a connection electrode, wherein the upper electrode is electrically connected to the common power line through a via. The method of claim 11 or 12, The organic light emitting display device of claim 1, wherein the first electrode comprises an anode electrode. The method of claim 13, The anode electrode includes Ag. The method of claim 14, And the anode electrode is made of ITO / Ag / ITO. A drive circuit board; A first semiconductor layer of the first TFT and a second semiconductor layer of the second TFT, each having a source region, a drain region, and a channel region and disposed in a sub pixel region of the driving circuit board; A gate insulating layer formed on the first semiconductor layer and the second semiconductor layer; A scan line integrally formed with the first gate electrode of the first TFT, the second gate electrode of the second TFT, and the first gate electrode formed on the gate insulating film; An interlayer insulating layer formed on the first and second gate electrodes, the scan line, and the gate insulating layer; A data line disposed on the interlayer insulating layer so as to be orthogonal to the scan line, a source electrode formed integrally with the data line and electrically connected to a source region of the first TFT, and provided on the same layer by the same material as the source electrode A drain electrode electrically connected to the drain region of the first TFT; A planarization film disposed over the data line, the source electrode and the drain electrode of the first TFT, and the interlayer insulating film; A first electrode having a drain electrode portion for a second TFT electrically connected to a drain region of the second TFT through a via, a light emitting layer provided on the first electrode, and a second electrode provided on the light emitting layer A light emitting device provided on the planarization film; And A common power line provided on the same layer of the same material as the first electrode and having a source electrode portion for a second TFT electrically connected to a source region of the second TFT. An organic light emitting display comprising a. The method of claim 16, The capacitor further comprises a lower electrode for a capacitor made of the same material as the second gate electrode and provided on an upper portion of the gate insulating layer, and an upper electrode for a capacitor provided between the interlayer insulating layer and the planarization layer. And an upper electrode electrically connected to the drain electrode of the first TFT, wherein the upper electrode is electrically connected to the common power line through a via. The method according to claim 16 or 17, The organic light emitting display device of claim 1, wherein the first electrode comprises an anode electrode. The method of claim 18, The anode electrode includes Ag. The method of claim 19, And the anode electrode is made of ITO / Ag / ITO. Forming a first semiconductor layer of the first TFT and a second semiconductor layer of the second TFT in the sub pixel region of the driving circuit board; Forming a gate insulating film; Forming a first gate electrode of the first TFT and a scan line connected to the electrode, a second gate electrode of the second TFT and a lower electrode for the capacitor connected to the electrode; Forming an interlayer insulating film; Forming an upper electrode for the capacitor; Forming a planarization film; A data line including a first source electrode portion electrically connected to a source region of the first semiconductor layer, a connection electrode electrically connecting the drain region and the lower electrode of the first semiconductor layer, and a source region of the second semiconductor layer electrically The first electrode having a second source electrode portion connected to each other, and having a common power line electrically connected to the upper electrode through a via and a second drain electrode portion electrically connected to the drain region of the second semiconductor layer may be formed of the same material. Forming on the planarization layer; And Sequentially stacking a light emitting layer and a second electrode on the first electrode Method of manufacturing an organic light emitting display device comprising a. Forming a first semiconductor layer of the first TFT and a second semiconductor layer of the second TFT in the sub pixel region of the driving circuit board; Forming a gate insulating film; Forming a first gate electrode of the first TFT and a scan line connected to the electrode, a second gate electrode of the second TFT and a lower electrode for the capacitor connected to the electrode; Forming an interlayer insulating film; A source electrode of the first TFT electrically connected to the source region of the first semiconductor layer, a data line integrally formed with the source electrode of the first TFT, and an electrically connecting drain region and the lower electrode of the first semiconductor layer. Forming a drain electrode of the first TFT and an upper electrode for the capacitor with the same material; Forming a planarization film; A common power line having a second source electrode portion electrically connected to the source region of the second semiconductor layer and electrically connected to the upper electrode through a via, and a second drain electrode electrically connected to the drain region of the second semiconductor layer Forming a first electrode having a portion of the same material as each other; And Sequentially stacking a light emitting layer and a second electrode on the first electrode Method of manufacturing an organic light emitting display device comprising a.

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