KR101746841B1 - Organic light emitting diode display device and manufacturing method of the same - Google Patents

Abstract

The present invention relates to an organic light emitting diode display and a method of manufacturing the same. An organic light emitting diode display device according to the present invention includes: a substrate; An organic light emitting diode formed on a substrate; A buffer layer covering the organic light emitting diode; And a thin film transistor connected to the organic light emitting diode formed on the buffer layer. INDUSTRIAL APPLICABILITY The organic light emitting diode display device according to the present invention uses a whole pixel region as an emission region as it is, and has a bright and clear image quality and can operate with a small driving current, thereby reducing power consumption, improving reliability of a device, Can be extended.

Description

Technical Field [0001] The present invention relates to an organic light emitting diode (OLED) display device and a method of manufacturing the same,

The present invention relates to an organic light emitting diode display and a method of manufacturing the same. In particular, the present invention relates to a bottom emission type organic light emitting diode display device using a whole pixel region as a light emitting region and not requiring a sealing material for device protection, and a manufacturing method thereof.

2. Description of the Related Art Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of cathode ray tubes (CRTs), have been developed. Such flat panel display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electroluminescence device (EL) have.

Among them, electroluminescent devices are divided into an inorganic electroluminescent device and an organic light emitting diode device depending on the material of the light emitting layer, and are self-luminous devices that emit themselves, have a high response speed, and have a large luminous efficiency, brightness and viewing angle. 1 is a view showing a structure of an organic light emitting diode. The organic light emitting diode includes an organic electroluminescent compound layer that electroluminesces as shown in FIG. 1 and a cathode electrode and an anode that face each other with the organic electroluminescent compound layer interposed therebetween. The organic electroluminescent compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer layer, EIL). In such an organic light emitting diode, an excitation is formed in the excitation process when the holes and electrons injected into the anode electrode and the cathode electrode recombine with each other in the emission layer (EML) And emits light.

The organic light emitting diode display device displays an image by electrically controlling the amount of light generated from the emission layer (EML) of the organic light emitting diode as shown in FIG. The organic light emitting diode display (OLEDD) may include a passive matrix type organic light emitting diode (PMOLED) display device and an active matrix type organic light emitting diode (OLED) display device Active Matrix type Organic Light Emitting Diode Display (AMOLED).

An active matrix type organic light emitting diode (AMOLED) display device displays a picture by controlling a current flowing in an organic light emitting diode using a thin film transistor (TFT). 2 is a plan view showing the structure of one pixel in AMOLED according to FIG. 3 is a cross-sectional view showing the structure of an AMOLED cut in a cutting line A-A 'in FIG. 2 to 3, the active matrix organic light emitting diode display device includes a switching thin film transistor SWTFT, a driving TFT DRTFT connected to the switching TFT SWTFT, an organic light emitting diode OLED connected to the driving TFT DRTFT, .

The switching TFT (SWTFT) is formed at a portion where the scan line (SL) and the data line (DL) cross each other. The switching TFT (SWTFT) functions to select a pixel. The switching TFT SWTFT includes a gate electrode GSW, a semiconductor layer ASW, a source electrode SSW, and a drain electrode DSW which branch from the scan line SL. The driving TFT DRTFT serves to drive the organic light emitting diode OLED of the pixel selected by the switching TFT SWTFT. The driving TFT DRTFT includes a gate electrode GDR connected to the drain electrode DSW of the switching TFT SWTFT, a source electrode SDR connected to the semiconductor layer ADR, the driving current transfer wiring VDD, (DDR). The drain electrode DDR of the driving TFT DRTFT is connected to the anode electrode ANO of the organic light emitting diode OLED.

4, gate electrodes GSW and GDR of a switching TFT SWTFT and a driving TFT DRTFT are formed on a substrate SUB of an active matrix organic light emitting diode display device. A gate insulating film GI covers the gate electrodes GSW and GDR. Semiconductor layers ASW and ADR are formed on a part of the gate insulating film GI which overlaps with the gate electrodes GSW and GDR. The source electrodes SSW and SDR and the drain electrodes DSW and DDR are formed facing each other on the semiconductor layers ASW and ADR at regular intervals. The drain electrode DSW of the switching TFT SWTFT is in contact with the gate electrode GDR of the driving TFT DRTFT through the contact hole formed in the gate insulating film GI. A protective layer (PASI) covering the switching TFT (SWTFT) and the driving TFT (DRTFT) having such a structure is applied over the entire surface. An anode electrode ANO of the organic light emitting diode OLED is formed on the passivation layer PASI. Here, the anode electrode ANO is connected to the drain electrode DDR of the driving TFT DRTFT through the contact hole formed in the passivation layer PASI.

Emitting region in which a switching TFT (SWTFT), a driving TFT (DRTFT), various wirings (DL, SL, VDD) are formed and a light emitting region in which an organic light emitting diode (OLED) is formed are formed on a substrate on which an anode electrode To form a bank pattern (BANK) to be divided. When the organic film EL is formed on the surface where the TFTs (SWTFT, DRTFT) and the various wirings DL, SL, VDD are formed and the surface is not smooth and ruggedly stepped, the bank pattern BANK In order to prevent deterioration of the organic matter in the part. That is, a non-emission region in which a switching TFT (SWTFT), a driving TFT (DRTFT), various wirings (DL, SL, VDD) are formed and a non-emission region A bank pattern BANK is formed. Therefore, the light emitting region is determined by the bank pattern BANK.

And the anode electrode ANO is exposed by the bank pattern BANK. The organic layer EL and the cathode electrode layer CAT are sequentially stacked on the bank pattern BANK and the anode electrode ANO.

In the organic light emitting diode display device having such a structure, the pixel region is determined to have a substantially rectangular shape surrounding the scan line SL, the data line DL, and the drive current line VDD. The actual light emitting region in the pixel region is determined by the anode electrode ANO exposed by the bank pattern BANK. As described above, the various wirings SL, DL, VDD, the switching TFT SWTFT, and the driving TFT DRTFT are non-emission regions. In this structure, the light emitting portion is usually about 30% of the total area. It is inevitably inefficient in terms of area.

In addition, the organic electroluminescent compound layer (EL) forming the OLED which is a main component of the organic light emitting diode display device is easily deteriorated by moisture or oxygen. Therefore, the organic light emitting diode display device has the sealing structure as shown in Fig. 4 is a cross-sectional view illustrating an organic light emitting diode display device having a sealing structure according to a related art.

An organic light emitting diode layer OLEDL including thin film transistors SWTFT and DRTFT and an organic layer EL is formed on a substrate SUB. The organic light emitting diode OLEDL is formed mainly in the central portion of the substrate SUB and a pad portion PAD for transmitting and receiving electric signals from an external device driving the organic light emitting diode display device is formed in the peripheral portion. The sealing glass substrate ENCAP is attached to the boundary portion with the pad portion PAD using the sealant SEAL containing the ultraviolet hardening resin material to protect the organic light emitting diode layer OLEDL from moisture and oxygen penetration from the outside do. Since moisture permeation from the outside can not be effectively prevented by using only the UV sealing material SEAL, a moisture absorptive material (GET) for absorbing moisture and oxygen permeating is attached to the central part of the sealing glass substrate ENCAP, Layer OLEDL.

The organic light emitting diode display device having such an encapsulation structure has an encapsulation substrate (ENCAP) and a hygroscopic material (GET) and requires a sealing process using a sealing material (SEAL). In addition, since the portion where the organic light emitting diode OLEDL is formed has an empty structure, the encapsulation substrate ENCAP can not maintain a horizontal state in the case of a large area display device, and can bend and affect the display device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an efficient organic light emitting diode display device and a method of manufacturing the same, which can utilize the entire pixel region as an emission region as it is. Another object of the present invention is to provide an organic light emitting diode display device and a manufacturing method thereof that do not require a sealing structure for protecting an organic layer from external moisture penetration.

According to an aspect of the present invention, there is provided an organic light emitting diode display comprising: a substrate; An organic light emitting diode formed on a substrate; A buffer layer covering the organic light emitting diode; And a thin film transistor connected to the organic light emitting diode formed on the buffer layer.

A scan line formed on the buffer layer, a data line orthogonal to the scan line, and a drive current wiring parallel to the data line; Wherein the thin film transistor includes a gate electrode, a source electrode corresponding to a portion of the driving current wiring, and a drain electrode facing the source electrode; And the organic light emitting diode is connected to the drain electrode.

The organic light emitting diode includes: a first electrode formed on the substrate; An organic light emitting layer formed on the first electrode; And a second electrode formed on the organic light emitting layer; And one of the first electrode and the second electrode is connected to the drain electrode.

The first electrode having a size corresponding to a pixel region; And the drain electrode is connected to the organic light emitting layer, the second electrode, and the contact hole passing through the buffer layer.

The first electrode is formed on the entire surface of the substrate; The second electrode has a size corresponding to a pixel region and is connected to the drain electrode through a contact hole passing through the buffer layer.

And the first electrode includes a transparent conductive material such as ITO and IZO.

A switching gate electrode branched at the scan line; A switching source electrode branched at the data line; And a switching thin film transistor including a switching drain electrode facing the switching source electrode and connected to a gate electrode of the thin film transistor.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting diode display device, including: forming an organic light emitting diode including a first electrode, an organic layer, and a second electrode on a substrate; Forming a buffer layer on the organic light emitting diode; And forming a thin film transistor for driving the organic light emitting diode on the buffer layer.

The forming of the organic light emitting diode includes depositing and patterning a conductive material on the substrate to form the first electrode to have a size corresponding to the pixel region; Forming a barrier rib on a part of the first electrode; And depositing an organic material and a conductive material lower than the height of the barrier rib to form the organic layer and the second electrode.

The forming of the organic light emitting diode includes sequentially forming a first electrode and an organic layer by continuously depositing a conductive material and an organic light emitting material on the entire surface of the substrate; Depositing a conductive material on the organic layer, and patterning to form a second electrode having a size corresponding to the pixel region.

The organic light emitting diode display device according to the present invention can use the entire pixel region as it is as a light emitting region, so that the organic light emitting diode display device has brighter and clearer picture quality, can operate with less driving current, And the service life can be further extended. Further, in the organic light emitting diode display device according to the present invention, since the organic layer is formed on the substrate and the TFT is formed thereon, the organic layer is completely protected. Therefore, a sealing structure for protecting the organic layer is not additionally required. As a result, since the organic layer is protected more effectively and the special sealing structure is not required, the manufacturing method is simple, the manufacturing cost is reduced, and the reliability of the device can be further improved.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 5 is a plan view showing an organic light emitting diode display device according to the present invention. 6A to 6H are cross-sectional views illustrating a method of manufacturing the organic light emitting diode display device according to the first embodiment of the present invention with a cross section taken along the perforated line I-I 'of FIG. FIGS. 7A to 7E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display device according to a second embodiment of the present invention, which is a cross section taken along the cutting line I-I 'of FIG.

Referring to FIG. 5, a plurality of scan lines SL running in the horizontal direction are arranged in the vertical direction. A plurality of data lines DL running in the longitudinal direction are arranged in the longitudinal direction. Further, the driving current wiring VDD is arranged close to each data line DL in parallel. A substantially rectangular shape formed while surrounding the scan line SL, the data line DL, and the drive current wiring VDD becomes the pixel region PA. Particularly, in order to secure the maximum pixel area, it is preferable to design the pixel area PA so that the wirings forming the boundary with neighboring pixels can be shared by 1/2 in both pixels.

The switching TFT SWTFT is formed at the intersection of the scan line SL and the data line DL. The switching TFT (SWTFT) functions to select a pixel. The switching TFT SWTFT includes a gate electrode GSW, a semiconductor layer ASW, a source electrode SSW, and a drain electrode DSW which branch from the scan line SL. The driving TFT DRTFT serves to drive the organic light emitting diode OLED of the pixel selected by the switching TFT SWTFT. The driving TFT DRTFT includes a gate electrode GDR connected to the drain electrode DSW of the switching TFT SWTFT, a source electrode SDR connected to the semiconductor layer ADR, the driving current transfer wiring VDD, (DDR). The drain electrode DDR of the driving TFT DRTFT is connected to the anode electrode ANO of the organic light emitting diode OLED.

In the organic light emitting diode display device according to the present invention, a switching TFT (SWTFT) and a driving TFT (DRTFT) occupy almost all areas in the pixel region PA. The anode electrode, the organic layer, and the cathode electrode for determining the light emitting region are formed below the TFTs (SWTFT, DRTFT), as viewed from the top surface of the substrate. Therefore, the ratio of the area occupied by the TFTs in the pixel area PA is free from any design. That is, in addition to the switching TFT (SWTFT) and the driving TFT (DRTFT), two to four compensating TFTs for compensating for the TFT operation can be additionally arranged freely in the pixel region PA.

6A to 6H, a method of manufacturing the organic light emitting diode display device according to the first embodiment will be described. A transparent conductive material such as ITO or IZO is deposited on the transparent substrate 101. The transparent conductive material is patterned with the first mask to form the anode electrode ANO corresponding to the pixel area PA. (Fig. 6A)

A barrier rib W is formed on a portion of the anode electrode ANO where a contact hole to be connected to the drain electrode DDR of the driving TFT DRTFT is to be formed. (Fig. 6B)

The organic layer EL and the cathode electrode CAT are continuously deposited on the substrate 101 on which the barrier rib W is formed. At this time, the organic layer EL and the cathode electrode CAT are formed to be lower than the height of the barrier rib W. When the color filter is not separately formed, the organic layer EL is preferably a color organic layer. If the organic layer EL is a white organic material, a color filter layer may be further formed under the organic layer. (Fig. 6C)

The partition wall W is removed using a lift off method. Then, a buffer layer (BUF) is deposited on the entire surface of the substrate. The buffer layer (BUF) is preferably coated with an organic material such as resin to planarize the substrate surface. (Fig. 6D)

A metal material is deposited on the buffer layer BUF and patterned with a second mask to form the gate electrode GSW of the switching TFT SWTFT and the gate electrode GDR of the driving TFT DRTFT. The gate electrode GSW of the switching TFT SWTFT is branched at the scan line SL. (Fig. 6E)

The gate insulating film GI is entirely deposited on the substrate 101 on which the gate electrodes GSW and GDR are formed. A semiconductor material is deposited on the gate insulating film GI and then patterned with a third mask to form semiconductor layers ASW and ADR on the gate electrodes GSW and GDR. (Figure 6f)

A first contact hole CH1 for exposing a part of the driving TFT DRTFT is formed by patterning the gate insulating film GI and the buffer layer BUF with a fourth mask and an anode electrode ANO at a place where the removed partition wall W is located. Thereby forming a second contact hole CH2 exposing a part thereof. The semiconductor layers ASW and ADR and the contact holes CH1 and CH2 are simultaneously formed through a single mask process by using a halftone mask in the first embodiment You may. (Fig. 6G)

A metal layer is deposited on the entire surface of the substrate and the source electrodes SSW and SDR and the drain electrodes DSW and DDR are formed on the semiconductor layers ASW and ADR with a predetermined gap therebetween by patterning with a fifth mask. The drain electrode DSW of the switching TFT SWTFT is connected to the gate electrode GDR of the driving TFT DRTFT through the first contact hole CH1 formed in the gate insulating film GI. The drain electrode DDR of the driving TFT DRTFT is connected to the anode electrode ANO located in the lowest layer through the second contact hole CH2. The source electrode SSW of the switching TFT SWTFT is branched at the data line DL and the source electrode SDR of the driving TFT DRTFT is formed as a part of the driving current wiring VDD. If necessary, a protective layer (PASI) for protecting the thin film transistors (SWTFT, DRTFT) may further be formed on the entire surface of the substrate. (Fig. 6H)

Hereinafter, a method of manufacturing the organic light emitting diode display device according to the second embodiment will be described with reference to FIGS. 7A to 7E.

A transparent conductor such as ITO or IZO is entirely deposited on the transparent substrate 101 to form a cathode layer (CAT). Then, an organic light emitting material is entirely deposited thereon to form an organic layer (EL). Then, a metal material is deposited on the organic layer (EL). The cathode layer (CAT), the organic layer (EL), and the metal material may be continuously deposited. Then, a metal material is patterned with the first mask to form the anode electrode ANO corresponding to the size of the pixel region. (Fig. 7A)

A buffer layer BUF is deposited on the entire surface of the substrate 101 on which the anode electrode ANO is formed. The buffer layer (BUF) is preferably coated with an organic material such as resin to planarize the substrate surface. A metal material is deposited on the buffer layer BUF and patterned with a second mask to form the gate electrode GSW of the switching TFT SWTFT and the gate electrode GDR of the driving TFT DRTFT. The gate electrode GSW of the switching TFT SWTFT is branched at the scan line SL. (Fig. 7B)

A gate insulating film (GI) is entirely coated on the gate electrodes (GSW, GDR). A semiconductor material is deposited on the gate insulating film GI and patterned with a third mask to form semiconductor layers ASW and ADR on the gate electrodes GSW and GDR, respectively. (Fig. 7C)

The gate insulating film GI and the buffer layer BUF are patterned with a fourth mask to form a first contact hole CH1 for exposing a part of the driving TFT DRTFT and a second contact hole CH2 for exposing a part of the anode electrode ANO ). The semiconductor layers ASW and ADR and the contact holes CH1 and CH2 are simultaneously formed through a single mask process using a halftone mask. You may. (Figure 7d)

A metal layer is deposited on the entire surface of the substrate and the source electrodes SSW and SDR and the drain electrodes DSW and DDR are formed on the semiconductor layers ASW and ADR with a predetermined gap therebetween by patterning with a fifth mask. The drain electrode DSW of the switching TFT SWTFT is connected to the gate electrode GDR of the driving TFT DRTFT through the first contact hole CH1 formed in the gate insulating film GI. The drain electrode DDR of the driving TFT DRTFT is connected to the anode electrode ANO via the second contact hole CH2. The source electrode SSW of the switching TFT SWTFT is branched at the data line DL and the source electrode SDR of the driving TFT DRTFT is formed as a part of the driving current wiring VDD. If necessary, a protective layer (PASI) for protecting the thin film transistors (SWTFT, DRTFT) may further be formed on the entire surface of the substrate. (Fig. 7E)

According to the first and second embodiments, the organic light emitting diode display device can be manufactured through the mask steps 4 to 5. In the organic light emitting diode display device having the structure shown in FIGS. 6H and 7E, the light emitting region is determined by the size of the anode electrode ANO. Since the anode electrode ANO has a size substantially equal to the size of the pixel region, the light emitting region and the pixel region have substantially the same size. Further, since the organic light emitting diode is not formed after the TFT is manufactured, the organic light emitting diode is first formed on the surface-smooth substrate, so that the bank pattern is not required. That is, it is possible to secure a maximum aperture ratio that is not affected by the thin film transistors (SWTFT, DRTFT) and various wirings (DL, SL, VDD).

Since the organic light emitting diode is formed first on the substrate and the bottom emission type is used, a light emitting region having an area ratio almost equal to the size of the pixel region can be obtained. In addition, since the thin film transistor is formed on the organic light emitting diode rather than the light emitting direction, the degree of freedom in determining the arrangement position and size of the thin film transistor is very high. Further, auxiliary thin film transistors for preventing the switching voltage of the thin film transistors from being shifted may be additionally formed.

In the embodiments of the present invention, the bottom emission method has been mainly described in order to secure the aperture ratio at the maximum. Therefore, a transparent electrode was formed on a glass substrate, and an opaque electrode was used on the organic layer. The transparent electrode may be an anode electrode of the organic light emitting diode or a cathode electrode. In Embodiment 1, a transparent electrode is applied to the anode electrode ANO, and in Embodiment 2, a transparent electrode is applied to the cathode electrode CAT. The structure in which the drain electrode of the driving TFT DRTFT is connected to the anode electrode ANO has been mainly described. The circuit configuration of the organic light emitting diode display device according to the present invention can be implemented as shown in FIGS. 8A and 8B. 8A to 8B are equivalent circuit diagrams showing the structure of an organic light emitting diode display device according to the present invention. However, since this is the most preferred embodiment, it can be applied to any structure as much as necessary.

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. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a structure of an organic light emitting diode. FIG.

2 is a plan view showing the structure of one pixel in the organic light emitting diode according to FIG.

3 is a cross-sectional view showing the structure of an organic light emitting diode cut to a perforated line A-A 'in FIG. 3;

4 is a sectional view showing an organic light emitting diode display device having a sealing structure according to a related art.

5 is a plan view showing an organic light emitting diode display device according to the present invention.

FIGS. 6A to 6H are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display device according to Embodiment 1 of the present invention, which is a section taken along the cutting line I-I 'of FIG.

FIGS. 7A to 7E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display device according to a second embodiment of the present invention, which is a section taken along the cutting line I-I 'of FIG.

8A to 8B are equivalent circuit diagrams showing the structure of an organic light emitting diode display device according to the present invention.

Description of the Related Art

HIL: Hole injection layer HTL: Hole transport layer

EML: light emitting layer ETL: electron transporting layer

EIL: electron injection layer BANK: bank pattern

OLED: organic light emitting diode layer PAD: pad portion

SUB: Substrate SEAL: Reality

ENCAP: Glass substrate for sealing GET: Absorbent material

DL: data line SL: scan line

SWTFT: switching TFT DRTFT: driving TFT

OLED: organic light emitting diode VDD: drive current wiring

CAT: cathode electrode ANO: anode electrode

EL: organic layer

GSW, GDR: gate electrode SSW, SDR: source electrode

DSW, DDR: drain electrode ASW, ADR: semiconductor layer

GI: Gate insulating film PASI: Shielding film

BANK: Bank pattern BUF: Buffer metal layer

101: transparent substrate W: partition wall

CH1: first contact hole CH2: second contact hole

Claims (15)

A liquid crystal display comprising: a substrate having a plurality of pixel regions arranged in a matrix manner; And a cathode electrode formed on the substrate, the anode electrode having a size corresponding to one pixel region and made of a transparent conductive material, the organic light emitting layer formed on the anode electrode, and the opaque conductive material formed over the entire surface of the organic light emitting layer Organic light emitting diodes; A buffer layer covering the organic light emitting diode; A scan line formed on the buffer layer; A data line orthogonal to the scan line; A driving current wiring parallel to the data line; And And a thin film transistor connected to the organic light emitting diode, the thin film transistor including a gate electrode, a source electrode corresponding to a portion of the driving current wiring, and a drain electrode facing the source electrode, on the buffer layer, Wherein the drain electrode is connected to the anode electrode through a contact hole passing through the organic light emitting layer, the cathode electrode, and the buffer layer. delete delete delete delete delete The method according to claim 1, A switching gate electrode branched at the scan line; A switching source electrode branched at the data line; Further comprising a switching thin film transistor including a switching drain electrode which is opposite to the switching source electrode and is connected to a gate electrode of the thin film transistor. Depositing and patterning a transparent conductive material on the substrate to form an anode electrode having a size corresponding to the pixel region; Forming a barrier rib on a part of the anode electrode; Forming an organic layer and a cathode electrode by depositing an organic material and an opaque conductive material lower than the height of the barrier rib to complete the organic light emitting diode; Removing the partition; Forming a buffer layer on the organic light emitting diode; A contact hole exposing the anode electrode at a position of the removed partition and a thin film transistor for driving the organic light emitting diode on the buffer layer, And the thin film transistor and the organic light emitting diode are connected to each other through the contact hole. delete 9. The method of claim 8, Wherein forming the thin film transistor comprises: Forming a gate electrode on the buffer layer; Forming a gate insulating film covering the gate electrode; Forming a semiconductor layer overlying the gate electrode on the gate insulating layer; Patterning the gate insulating layer to form the contact hole exposing the anode electrode at a position of the removed partition; Forming a source electrode on one side of the semiconductor layer and a drain electrode facing the source electrode on the other side of the semiconductor layer and in contact with the anode electrode through the contact hole, A method of manufacturing a diode display device. 11. The method of claim 10, The forming of the gate electrode may further include forming a scan line and a switching gate electrode branching from the scan line; The step of forming the semiconductor layer further includes forming a switching semiconductor layer overlying the switching gate electrode on the gate insulating film; The forming of the contact hole may further include forming a gate contact hole that exposes a part of the gate electrode by patterning the gate insulating film; Wherein the step of forming the source electrode and the drain electrode comprises the steps of forming a gate electrode on the one side of the switching semiconductor layer and a gate electrode on the other side of the switching semiconductor layer, Wherein the organic light emitting diode display further comprises a switching drain electrode that is in contact with the electrode. delete delete delete delete

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