KR102247825B1 - Bottom Emission Type Organic Light Emission Diode Display Having Color Filters And Method For Manufacturing The Same - Google Patents

Abstract

The present invention relates to a bottom emission type organic light emitting diode display device having a color filter and a method of manufacturing the same. An organic light emitting diode display according to the present invention includes: a black matrix defining a light emitting area on a substrate; A color filter formed in the light emitting area; A buffer layer applied on the color filter; A thin film transistor formed on the buffer layer and an anode electrode connected to the thin film transistor; A protective layer covering the thin film transistor and the anode electrode; An opening formed in the passivation layer to open the anode electrode to correspond to the light emitting area; An organic light-emitting layer applied on the protective layer and stacked on the anode electrode at the opening; And a cathode electrode applied on the organic light-emitting layer and stacked with the organic light-emitting layer in the opening.

Description

Bottom Emission Type Organic Light Emission Diode Display Having Color Filters And Method For Manufacturing The Same}

The present invention relates to a bottom emission type organic light emitting diode display device having a color filter and a method of manufacturing the same. In particular, the present invention relates to an organic light-emitting diode display and a method of manufacturing the same, in which a color filter is first formed on a substrate, and a thin film transistor and an organic light-emitting diode are stacked thereon.

Recently, various flat panel display devices capable of reducing the weight and volume, which are disadvantages of a cathode ray tube, have been developed. Such flat panel displays include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP), and Electroluminescence Device (EL). There is this.

Electroluminescent display devices are roughly classified into inorganic electroluminescent display devices and organic light emitting diode display devices according to the material of the light emitting layer. As a self-luminous device that emits light, it has a fast response speed, and has great advantages in luminous efficiency, luminance, and viewing angle.

1 is a diagram showing the structure of a general organic light emitting diode. The organic light emitting diode includes an organic electroluminescent compound layer that emits light as shown in FIG. 1, and a cathode electrode and an anode electrode facing each other with the organic electroluminescent compound layer 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 the organic light emitting diode, excitons are formed during the excitation process when holes and electrons injected into the anode and cathode electrodes recombine in the emission layer EML, and emit light due to energy from the excitons. The organic light-emitting diode display device displays an image by electrically controlling the amount of light emitted from the emission layer EML of the organic light-emitting diode as shown in FIG. 1.

The organic light emitting diode display (OLEDD) using the characteristics of the organic light emitting diode, which is an electroluminescent device, includes a passive matrix type organic light emitting diode display (PMOLED) and an active matrix. It is roughly classified as an Active Matrix type Organic Light Emitting Diode display (AMOLED).

An active matrix type organic light emitting diode display (AMOLED) uses a thin film transistor (or "TFT") to control the current flowing through the organic light emitting diode to display an image. 2 is an example of an equivalent circuit diagram showing the structure of one pixel in a general organic light emitting diode display. 3 is a plan view showing a structure of one pixel in an organic light emitting diode display according to the prior art. FIG. 4 is a cross-sectional view showing the structure of an organic light emitting diode display according to the prior art, cut along the perforated line I-I' in FIG. 3.

2 to 3, the active matrix organic light emitting diode display includes a switching thin film transistor ST, a driving TFT DT connected to the switching TFT, and an organic light emitting diode OLED connected to the driving TFT DT. . The switching TFT ST is formed at a portion where the scan line SL and the data line DL intersect. The switching TFT (ST) functions to select a pixel. The switching TFT ST includes a gate electrode SG branching from the scan wiring SL, a semiconductor layer SA, a source electrode SS, and a drain electrode SD.

In addition, the driving TFT DT serves to drive the organic light emitting diode OLED of the pixel selected by the switching TFT ST. The driving TFT DT includes a gate electrode DG connected to the drain electrode SD of the switching TFT ST, a semiconductor layer DA, a source electrode DS connected to the driving current line VDD, and a drain electrode ( DD). The drain electrode DD of the driving TFT DT is connected to the anode electrode ANO of the organic light emitting diode OLED.

Referring to FIG. 4 to examine in more detail, in the active matrix organic light emitting diode display, gate electrodes SG and DG of the switching TFT ST and the driving TFT DT are formed on a transparent substrate SUB. have. In addition, the gate insulating film GI is covering the gate electrodes SG and DG. The semiconductor layers SA and DA are formed on a part of the gate insulating film GI overlapping the gate electrodes SG and DG. Source electrodes SS and DS and drain electrodes SD and DD are formed on the semiconductor layers SA and DA at regular intervals to face each other. The drain electrode SD of the switching TFT ST contacts the gate electrode DG of the driving TFT DT through a contact hole formed in the gate insulating film GI. A protective layer (PAS) covering the switching TFT (ST) and the driving TFT (DT) having such a structure is applied on the entire surface.

In particular, when the semiconductor layers SA and DA are formed of an oxide semiconductor material, it is advantageous for high resolution and high speed driving in a large area thin film transistor substrate having a large charging capacity due to high charge mobility characteristics. However, it is preferable that the oxide semiconductor material further includes an etch stopper (SE, DE) for protection from an etchant on the upper surface in order to secure the stability of the device. Specifically, protects the semiconductor layers (SA, DA) from being back etched from the etchant in contact with the exposed upper surface at the spaced portion between the source electrodes (SS, DS) and the drain electrodes (SD, DD). Etch stoppers (SE, DE) are formed so as to be performed.

The color filter CF is formed in a portion corresponding to the area of the anode electrode ANO to be formed later. It is preferable to form the color filter CF to occupy as large an area as possible. For example, it is preferable to form the data line DL, the driving current line VDD, and the plurality of regions of the scan line SL at the front end to overlap each other. In the substrate on which the color filter CF is formed as described above, the surface of the substrate on which the color filter CF is formed is not flat and has many steps. Accordingly, the overcoat layer OC is applied to the entire surface of the substrate for the purpose of making the surface of the substrate flat.

In addition, the anode electrode ANO of the organic light emitting diode OLED is formed on the overcoat layer OC. Here, the anode electrode ANO is connected to the drain electrode DD of the driving TFT DT through a contact hole formed in the overcoat layer OC and the protective layer PAS.

On the substrate on which the anode electrode ANO is formed, a bank pattern BN is formed on a region in which the switching TFT (ST), the driving TFT (DT), and various wires (DL, SL, VDD) are formed to define a pixel region. . The anode electrode ANO exposed by the bank pattern BN becomes a light emitting area.

An organic light emitting layer OLE and a cathode electrode layer CAT are sequentially stacked on the anode electrode ANO exposed by the bank pattern BN. When the organic light-emitting layer OLE is made of an organic material emitting white light, the color assigned to each pixel is indicated by the color filter CF located below. The organic light emitting diode display having the structure as shown in FIG. 4 becomes a bottom emission display device that emits light in a downward direction.

In such an organic light emitting diode display, a viewer observes video information from the light emitting side, and when viewed from the observation direction, various wires, particularly the scan wire SL and the gate electrode G, are exposed as it is. If external light is reflected by these metal wires, it may interfere with the spectator's observation of video information. To prevent this problem, a polarizing plate is attached to the outer surface of the substrate SUB. As a result, there is a problem that the luminous efficiency of the display device is lowered.

In addition, when an oxide semiconductor material having excellent driving characteristics is used, a top gate structure must be applied unlike FIG. 4. However, since the properties of the oxide semiconductor material are easily changed by external light, a light shielding layer must be further formed between the substrate SUB and the thin film transistors ST and DT. Accordingly, there is a need for an organic light emitting diode display of a new structure capable of maximizing luminous efficiency by applying an oxide semiconductor material that is a bottom-emission type and having excellent characteristics, and preventing reflection of wiring without using a polarizing plate.

An object of the present invention is to overcome the above problems, by first forming a black matrix and a color filter on a substrate to improve reflection visibility and improve contrast effect, and a bottom-emitting type organic light emitting diode display device and manufacturing thereof There is a way to provide. Another object of the present invention is to simplify the manufacturing process and reduce manufacturing cost by having a structure in which an anode electrode is first formed in forming a thin film transistor and an organic light emitting diode on a color filter. A manufacturing method and a bottom emission type organic light emitting diode display device using the method are provided.

In order to achieve the object of the present invention, an organic light emitting diode display according to the present invention includes: a black matrix defining a light emitting area on a substrate; A color filter formed in the light emitting area; A buffer layer applied on the color filter; A thin film transistor formed on the buffer layer and an anode electrode connected to the thin film transistor; A protective layer covering the thin film transistor and the anode electrode; An opening formed in the passivation layer to open the anode electrode to correspond to the light emitting area; An organic light-emitting layer applied on the protective layer and stacked on the anode electrode at the opening; And a cathode electrode applied on the organic light-emitting layer and stacked with the organic light-emitting layer in the opening.

The thin film transistor may include a channel region formed of an oxide semiconductor material on the buffer layer, a source region extending to one side of the channel region and conducting the oxide semiconductor material, and extending to the other side of the channel region, the oxide semiconductor And a semiconductor layer including a drain region in which a material is conductive, and the anode electrode is formed by extending the drain region to the light emitting region.

The thin film transistor may include: a gate insulating layer and a gate electrode overlapping the channel region; An intermediate insulating layer covering the gate electrode and the semiconductor layer; A source contact hole formed in the intermediate insulating layer to expose the source region and a drain contact hole to expose the drain region; And a source electrode formed on the intermediate insulating layer and in contact with the source region and a drain electrode in contact with the drain region.

The thin film transistor includes: a source electrode in which a transparent conductive material and a metal material are stacked on the buffer layer; And a drain electrode facing the source electrode by a predetermined distance, wherein the anode electrode includes the drain electrode extending and extending to the light emitting region, and is made of only the transparent conductive material.

The thin film transistor includes: a semiconductor layer including an oxide semiconductor material formed therebetween while being in contact with the source electrode and the drain electrode; A gate insulating layer and a gate electrode overlapping the central region of the semiconductor layer to define a channel region; And an intermediate insulating layer covering the semiconductor layer and the gate electrode.

In addition, a method of manufacturing an organic light emitting diode display according to the present invention includes: forming a black matrix defining a light emitting area on a substrate; Forming a color filter filling the light emitting area; Forming a buffer layer on the color filter; Forming an anode electrode and a thin film transistor connected to the anode electrode on the buffer layer; Applying a protective film to cover the anode electrode and the thin film transistor, and forming an opening exposing the anode electrode to correspond to the light-emitting region; Applying an organic light emitting layer on the passivation layer so as to be stacked on the anode electrode at the opening; And applying a cathode electrode on the organic light-emitting layer.

The forming of the anode electrode and the thin film transistor may include applying and patterning an oxide semiconductor material on the buffer layer to form a semiconductor layer extending in a region where the thin film transistor is formed and a position where the anode electrode is formed; Forming a gate insulating layer and a gate electrode overlapping a portion of the semiconductor layer; Conducting the semiconductor layer using the gate electrode as a mask, a channel region overlapping with the gate electrode and not conductive, a source region conductive at one side of the channel region, and a conductor at the other side of the channel region And defining a drain region and the anode electrode extending from the drain region to the emission region.

In the forming of the anode electrode and the thin film transistor, the thin film transistor in which the transparent conductive material and the metal material are stacked by continuously depositing a transparent conductive material and a metal material on the buffer layer and patterned with a half-tone mask. Forming a source electrode and a drain electrode of, and the anode electrode formed of only the transparent conductive material and extending from the drain electrode to the light emitting region; Forming a semiconductor layer connecting the source electrode and the drain electrode with an oxide semiconductor material; Forming a gate insulating layer and a gate electrode overlapping the central portion of the semiconductor layer; And making the semiconductor layer conductive using the gate electrode as a mask, and defining a channel region that overlaps the gate electrode and is not conductive.

The present invention provides a bottom emission type organic light emitting diode in which a black matrix and a color filter are first formed on a substrate, and then a thin film transistor and an organic light emitting diode are formed. Accordingly, when viewed from the observation surface, the black matrix is arranged in a structure to cover the metal elements, thereby improving the reflection visibility and preventing mixing between colors, thereby improving contrast. In addition, by forming the anode electrode in the process of forming the semiconductor layer or forming the source-drain element at the same time, it is possible to substitute a protective film without separately forming a bank defining a light emitting region. Therefore, there is an advantage in that the manufacturing process is simple and the manufacturing cost is reduced.

1 is a diagram showing the structure of a general organic light emitting diode.
2 is an equivalent circuit diagram showing the structure of one pixel in a general organic light emitting diode display.
3 is a plan view showing a structure of one pixel in an organic light emitting diode display according to the prior art.
FIG. 4 is a cross-sectional view showing the structure of an organic light emitting diode display according to the prior art, cut along the perforated line I-I' in FIG.
5 is a plan view showing a structure of one pixel in the bottom emission type organic light emitting diode display according to the first embodiment of the present invention.
6 is a cross-sectional view showing the structure of the organic light emitting diode display according to the first embodiment of the present invention, cut by the cut line II-II' in FIG. 5.
7A to 7H are cross-sectional views illustrating a process of manufacturing an organic light emitting diode display according to the first embodiment of the present invention.
FIG. 8 is a cross-sectional view showing the structure of an organic light emitting diode display according to a second embodiment of the present invention, taken along a cut line II-II' in FIG. 5.
9A to 9I are cross-sectional views illustrating a process of manufacturing an organic light emitting diode display according to a second embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numbers throughout the specification mean substantially the same elements. In the following description, when it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Hereinafter, a bottom emission type organic light emitting diode display according to a first embodiment of the present invention will be described with reference to FIGS. 5 and 6. 5 is a plan view illustrating a structure of one pixel in the bottom emission type organic light emitting diode display according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view showing the structure of an organic light emitting diode display according to the prior art, cut along the perforated line II-II' in FIG. 5.

5 and 6, the bottom emission type organic light emitting diode display according to the first embodiment of the present invention includes a switching thin film transistor (ST), a driving TFT (DT) connected to the switching TFT, and a driving TFT (DT). It includes a connected organic light emitting diode (OLED). The switching TFT ST is formed at a portion where the scan line SL and the data line DL intersect. The switching TFT (ST) functions to select a pixel. The switching TFT ST includes a gate electrode SG branching from the scan wiring SL, a semiconductor layer SA, a source electrode SS, and a drain electrode SD.

In addition, the driving TFT DT serves to drive the organic light emitting diode OLED of the pixel selected by the switching TFT ST. The driving TFT DT includes a gate electrode DG connected to the drain electrode SD of the switching TFT ST, a semiconductor layer DA, a source electrode DS connected to the driving current line VDD, and a drain electrode ( DD). The drain electrode DD of the driving TFT DT is connected to the anode electrode ANO of the organic light emitting diode OLED.

In the present invention, there is a major feature in manufacturing an organic light emitting diode display device formed by stacking several elements by simplifying the manufacturing process. In addition, the structure of the organic light emitting diode display formed by the manufacturing method according to the present invention is also characterized.

In particular, in the bottom emission type organic light emitting diode display according to the first embodiment of the present invention, a black matrix BM and a color filter CF are first formed on a substrate SUB. For example, a black matrix BM is disposed at a location where the wirings SL, DL, and VDD and the thin film transistors ST and DT are to be formed, and a color filter ( CF). The black matrix BM has a structure that covers the thin film transistors ST and DT to be formed later and various wirings DL, SL, and VDD, and has a structure to open the light emission area, thereby defining a light emission area.

Thin film transistors should be formed on the surface of the substrate SUB on which the color filter CF is formed, and the buffer layer BUF is formed to cover the entire surface to maintain the interface characteristics and planarization characteristics of the thin film. A switching thin film transistor ST and a driving thin film transistor DT are formed on the buffer layer BUF.

In particular, in the first embodiment of the present invention, a thin film transistor is formed using an oxide semiconductor material. In addition, the anode electrode ANO constituting the organic light emitting diode OLE is formed by converting an oxide semiconductor material into a conductor. For example, an oxide semiconductor layer is formed on the buffer layer BUF. The oxide semiconductor layer is composed of a source region SSA, a channel region SA, and a drain region SDA of the switching thin film transistor ST. It also includes a source region DSA, a channel region DA, and a drain region DDA of the driving thin film transistor DT. In particular, the drain region DDA of the driving thin film transistor DT extends and extends so as to cover all of the opening regions of the pixel region to form the anode electrode ANO.

A gate insulating film GI and a gate electrode SG are stacked on the channel region SA of the switching thin film transistor ST, and the gate insulating film GI and the gate electrode are also on the channel region DA of the driving thin film transistor DT. (DG) is laminated. An intermediate insulating layer IL is coated on the entire surface of the substrate SUB on which the gate electrodes SG and DG are formed. Further, the intermediate insulating layer IL includes contact holes exposing a portion of the source region SSA and the drain region SDA of the switching thin film transistor ST, and the source region DSA and the gate of the driving thin film transistor DT. Contact holes exposing part of the electrode DG are formed. In addition, most of the anode electrode ANO integral with the drain region DDA of the driving thin film transistor DT is exposed.

A source-drain material is formed on the intermediate insulating layer IL. For example, a source electrode SS and a data line DL connected to the source region SSA of the switching thin film transistor ST, and a drain electrode SD connected to the drain region SDA are formed. In addition, a source electrode DS and a driving current line VDD connected to the source region DSA of the driving thin film transistor DT are formed. In addition, the drain electrode SD of the switching thin film transistor ST is connected to the gate electrode DG of the driving thin film transistor DT.

As described above, a passivation layer PAS is applied on the entire surface of the substrate SUB on which the switching thin film transistor ST, the driving thin film transistor DT, and the anode electrode ANO are formed to protect the source-drain elements. In addition, the protective film PAS is formed to expose most of the anode electrode ANO to form an opening defining a light emitting region. That is, in the first embodiment of the present invention, the protective layer PAS is formed to simultaneously satisfy the role of the bank BA. For example, it may be preferable that the passivation layer PAS includes an organic material used for the bank BA rather than being formed of an inorganic material.

The organic light emitting layer OL is coated on the entire surface of the substrate SUB on which the passivation layer PAS defining the light emitting area is formed. In addition, the cathode electrode CAT is applied on the organic light emitting layer OL to cover the entire substrate SUB.

In the first embodiment of the present invention, the channel layers SA and DA are formed of IGZO (Indium Galium Zinc Oxide) and an oxide semiconductor material, and the anode electrode ANO is also formed of the same oxide semiconductor material, and then the gate electrode SG , DG) is used as a mask to form an oxide semiconductor material into a conductor. Accordingly, since the anode electrode ANO has the same thickness as the channel layers SA and DA, it is possible to secure transparency and have conductivity. In addition, by forming the cathode electrode CAT of an opaque or semi-transparent metal material, the light generated from the organic light-emitting layer OL is a bottom-emitting type organic light-emitting diode display device in which color is realized by a color filter CF located below. do.

Hereinafter, a method of manufacturing a bottom emission type organic light emitting diode display according to a first embodiment of the present invention will be described in detail with reference to FIGS. 7A to 7H. 7A to 7H are cross-sectional views illustrating a process of manufacturing an organic light emitting diode display according to the first embodiment of the present invention.

A black matrix BM is formed on the transparent substrate SUB. The black matrix BM is preferably formed at a location where driving elements such as wirings and thin film transistors are to be formed. (Fig. 7a)

A color filter CF is formed on the substrate SUB on which the black matrix BM is formed. It is preferable to arrange the color filter CF to have a color assigned to each pixel. For example, red (R), green (G), and blue (B) color filters CF may be formed to be alternately disposed. In addition, a buffer layer BUF is formed on the entire surface of the substrate SUB on which the color filter CF is completed. (Fig. 7b)

An oxide semiconductor material such as Indum-Galium-Zinc-Oxide is coated on the buffer layer BUF. A semiconductor layer SE is formed by patterning an oxide semiconductor material. The semiconductor layer SE is formed to be separately disposed at a position where the switching thin film transistor ST is to be formed and a position where the driving thin film transistor DT is to be formed. In particular, the semiconductor layer SE of the driving thin film transistor DT is formed to extend and extend to the anode electrode ANO region. (Fig. 7c)

An insulating material and a gate metal material are continuously deposited on the entire surface of the substrate SUB on which the semiconductor layer SE is formed. A gate metal material and an insulating material are patterned by a mask process to form a gate insulating layer GI and gate electrodes SG and DG. Plasma treatment is performed on the semiconductor layer SE by using the gate electrodes SG and DG as masks to make conductors of portions not covered by the gate electrodes SG and DG. As a result, the semiconductor layer SE overlapping the gate electrode SG of the switching thin film transistor ST is defined as a channel layer SA, and on both sides thereof, a source region SSA and a drain region SDA are respectively defined. . Similarly, the semiconductor layer SE overlapping the gate electrode DG of the driving thin film transistor DT is defined as a channel layer DA, and both sides thereof are defined as a source region DSA and a drain region DDA, respectively. Particularly, a portion extending and extending from the drain region DDA to the opening region is completed with the anode electrode ANO. (Fig. 7d)

The intermediate insulating layer IL is coated on the entire surface of the substrate SUB on which the gate electrodes SG and DG and the anode electrode ANO are formed. The intermediate insulating layer IL is patterned to form a source contact hole SSH exposing the source region SSA of the switching thin film transistor ST and a drain contact hole SDH exposing the drain region SDA. In addition, a gate contact hole GH exposing a part of the gate electrode DG of the driving thin film transistor DT and a source contact hole DSH exposing the source region DSA are formed. In addition, a pixel opening PA exposing most of the anode electrode ANO is formed. (Fig. 7e)

A source-drain metal material is coated on the entire surface of the substrate SUB on which the contact holes SSH, SDH, GH, and DSH are formed. A source-drain material is patterned by a mask process to form a source-drain element. The source-drain elements include a source electrode SS in contact with the source region SSA of the switching thin film transistor ST, a data line DL connected to the source electrode SS, and a drain region of the switching thin film transistor ST. SDA) and the drain electrode SD of the switching thin film transistor ST in contact with the gate electrode DG of the driving thin film transistor DT, the source electrode in contact with the source region DSA of the driving thin film transistor DT (DS) and a driving current line (VDD) connected to the source electrode (DS). (Fig. 7f)

A passivation layer PAS is applied over the entire surface of the substrate SUB on which the source-drain elements are formed. The passivation layer PAS is formed to protect the completed thin film transistors ST and DT and various wirings DL and VDD from the outside. The protective layer PAS is patterned to expose the openings PA. That is, the passivation layer PAS simultaneously functions as a bank defining an opening area. (Fig. 7g)

The organic light-emitting layer OL is applied on the entire surface of the substrate SUB on which the passivation layer PAS including the opening PA exposing the anode electrode ANO is formed. When the organic light-emitting layer OL is formed of a white organic light-emitting material, it may be applied to cover the entire surface of the substrate SUB. On the other hand, red, green, and blue organic light emitting materials may be applied by dividing each pixel. The cathode electrode CAT is formed by coating an opaque metallic material or a translucent conductive material on the entire surface of the substrate SUB on which the organic light emitting layer OL is formed. As a result, the organic light emitting diode OLE is formed in the opening region in which the anode electrode ANO, the organic light emitting layer OL, and the cathode electrode CAT are stacked. (Fig. 7h)

Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 5 and 8. FIG. 8 is a cross-sectional view showing the structure of an organic light emitting diode display according to a second embodiment of the present invention, taken along a cut line II-II' in FIG. 5. The organic light emitting diode display according to the second embodiment has substantially the same structure as that of the first embodiment. If there is a difference, differences can be found in the structure of the thin film transistors ST and DT and the anode electrode ANO.

In the bottom emission type organic light emitting diode display according to the second embodiment of the present invention, a black matrix BM and a color filter CF are first formed on a substrate SUB. For example, a black matrix BM is disposed at a location where the wirings SL, DL, and VDD and the thin film transistors ST and DT are to be formed, and a color filter ( CF) is placed.

Thin film transistors ST and DT must be formed on the surface of the substrate SUB on which the color filter CF is formed, and the buffer layer BUF is formed to cover the entire surface to maintain the interface characteristics and planarization characteristics of the thin film. On the buffer layer BUF, a switching thin film transistor ST, a driving TFT DT connected to the switching TFT, and an organic light emitting diode OLED connected to the driving TFT DT are formed. The switching TFT ST is formed at a portion where the scan line SL and the data line DL intersect. The switching TFT (ST) functions to select a pixel. The switching TFT ST includes a gate electrode SG branching from the scan wiring SL, a semiconductor layer SA, a source electrode SS, and a drain electrode SD.

In addition, the driving TFT DT serves to drive the organic light emitting diode OLED of the pixel selected by the switching TFT ST. The driving TFT DT includes a gate electrode DG connected to the drain electrode SD of the switching TFT ST, a semiconductor layer DA, a source electrode DS connected to the driving current line VDD, and a drain electrode ( DD). The drain electrode DD of the driving TFT DT is connected to the anode electrode ANO of the organic light emitting diode OLED.

In particular, in the second embodiment of the present invention, source-drain elements constituting the thin film transistors ST and DT are first formed on the buffer layer BUF. In addition, an anode electrode ANO connected to the driving thin film transistor DT is directly formed on the buffer layer BUF. For example, the source-drain elements may have a structure in which a transparent conductive material layer and a metal material layer are stacked, and the anode electrode ANO may consist of only a transparent conductive material layer.

The source-drain element includes a data line DL connecting the source electrode SS and the drain electrode SD and the source electrode SS of the switching thin film transistor ST. In addition, the source-drain element includes a source electrode DS and a drain electrode DD of the driving thin film transistor DT, and a driving current line VDD connecting the source electrode DS. In addition, the drain electrode DD of the driving thin film transistor DT is integrally formed with the anode electrode ANO.

A semiconductor layer formed of an oxide semiconductor material is formed between the source and drain elements. A gate electrode SG of the switching thin film transistor ST and a gate electrode DG of the driving thin film transistor DT are formed on the semiconductor layer in a central region portion with a gate insulating layer GI therebetween. The semiconductor layers overlapping the gate electrodes SG and DG are defined as a channel region SA of the switching thin film transistor ST and a channel region DA of the driving thin film transistor ST, respectively. The semiconductor layer regions conducted on both sides of the channel regions SA and DA are respectively connected to the source-drain elements.

The intermediate insulating layer IL covering the switching thin film transistor ST and the driving thin film transistor DT covers the entire substrate SUB. A contact hole exposing the drain electrode SD of the switching thin film transistor ST and a contact hole exposing the gate electrode DG of the driving thin film transistor DT are formed in the intermediate insulating layer IL, respectively. Further, an opening region exposing most of the anode electrode ANO is formed.

A connection connecting the drain electrode SD of the switching thin film transistor ST and the gate electrode DG of the driving thin film transistor DT on the intermediate insulating layer IL, which is made of a metal material or a transparent conductive material on the intermediate insulating layer IL. An electrode is formed. Although not shown in the drawing, the pad terminal may be further formed of the same material as the connection electrode.

On the intermediate insulating layer IL, a protective layer PAS is applied over the entire surface of the substrate SUB. In the second embodiment as well, the passivation layer PAS functions as the bank BN. Accordingly, an opening region defining a light emitting region in the anode electrode ANO is formed in the passivation layer PAS.

The organic light-emitting layer OL is coated on the entire surface of the substrate SUB on which the passivation layer PAS is formed. On the organic light emitting layer OL, the cathode electrode CAT is applied over the entire surface. The organic light emitting diode OLE is formed by a structure in which the anode electrode ANO, the organic light emitting layer OL, and the cathode electrode CAT are stacked.

In addition, the anode electrode ANO constituting the organic light emitting diode OLE is formed by converting an oxide semiconductor material into a conductor. For example, an oxide semiconductor layer is formed on the buffer layer BUF. The oxide semiconductor layer is composed of a source region SSA, a channel region SA, and a drain region SDA of the switching thin film transistor ST. It also includes a source region DSA, a channel region DA, and a drain region DDA of the driving thin film transistor DT. In particular, the drain region DDA of the driving thin film transistor DT extends and extends so as to cover all of the opening regions of the pixel region to form the anode electrode ANO.

In the second embodiment of the present invention, the anode electrode (ANO) is formed of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) together with the source-drain elements of the thin film transistors (ST, DT). do. After that, the thin film transistors ST and DT are completed, and the organic light emitting diode OLE is completed. By forming the cathode electrode CAT of the organic light-emitting diode (OLE) with an opaque or translucent metal material, light generated from the organic light-emitting layer OL is a bottom-emitting type organic light-emitting diode in which color is realized by a color filter (CF) located below. It becomes a light emitting diode display device.

Hereinafter, a method of manufacturing an organic light emitting diode display according to a second embodiment of the present invention will be described with reference to FIGS. 9A to 9I. 9A to 9I are cross-sectional views illustrating a process of manufacturing an organic light emitting diode display according to a second embodiment of the present invention.

A black matrix BM is formed on the transparent substrate SUB. The black matrix BM is preferably formed at a location where driving elements such as wirings and thin film transistors are to be formed. (Fig. 9a)

A color filter CF is formed on the substrate SUB on which the black matrix BM is formed. It is preferable to arrange the color filter CF to have a color assigned to each pixel. For example, red (R), green (G), and blue (B) color filters CF may be formed to be alternately disposed. A buffer layer BUF is formed on the entire surface of the substrate SUB on which the color filter CF is completed. (Fig. 9b)

On the buffer layer BUF, a transparent conductive material such as ITO or IZO and a metal material are continuously applied. By patterning in a mask process, a source-drain element and an anode electrode ANO are formed. The source-drain elements include a source electrode SS and a drain electrode SD of the switching thin film transistor ST, a data line DL connected to the source electrode SS, and a source electrode DS of the driving thin film transistor DT. And a driving current line VDD connected to the drain electrode DD and the source electrode DS. It is preferable that the anode electrode ANO is formed of only a transparent conductive material, and the source-drain element has a structure in which a transparent conductive material and a metal material are stacked. Therefore, it is preferable to use a half-tone mask as the mask used at this time. The source electrode (SS) and drain electrode (SD) of the switching thin film transistor (ST), the data line (DL), the source electrode (DS) and drain electrode (DD) of the driving thin film transistor, and the driving current line (VDD) are electrically Since the signal needs to be transmitted evenly over the entire substrate SUB, it is preferable to include a metal material to have a low line resistance. In some cases, a metal material may be removed from some of the source-drain elements and may be made only of a transparent conductive material. (Fig. 9c)

An oxide semiconductor material such as Indum-Galium-Zinc-Oxide is coated on the surface of the substrate SUB on which the source-drain element and the anode electrode ANO are formed. A semiconductor layer SE is formed by patterning an oxide semiconductor material. The semiconductor layer SE is formed to be separately disposed at a position where the switching thin film transistor ST is to be formed and a position where the driving thin film transistor DT is to be formed. (Fig. 9d)

An insulating material and a gate metal material are continuously deposited on the entire surface of the substrate SUB on which the semiconductor layer SE is formed. A gate metal material and an insulating material are patterned by a mask process to form a gate insulating layer GI and gate electrodes SG and DG. Plasma treatment is performed on the semiconductor layer SE using the gate electrodes SG and DG as masks, and portions not covered by the gate electrodes SG and DG are made into conductors. As a result, the semiconductor layer SE overlapping the gate electrode SG of the switching thin film transistor ST is defined as the channel layer SA. Similarly, the semiconductor layer SE overlapping the gate electrode DG of the driving thin film transistor DT is defined as the channel layer DA. Accordingly, the switching thin film transistor ST and the driving thin film transistor DT are completed. (Fig. 9e)

An intermediate insulating layer IL is coated on the entire surface of the substrate SUB on which the switching thin film transistor ST and the driving thin film transistor DT are formed. The intermediate insulating layer IL is patterned to form a drain contact hole DH exposing the drain electrode SD of the switching thin film transistor ST. In addition, a gate contact hole GH exposing a part of the gate electrode DG of the driving thin film transistor DT is formed. In addition, a pixel opening PA exposing most of the anode electrode ANO is formed. (Fig. 9f)

A metal material or a transparent conductive material is coated on the entire surface of the substrate SUB on which the contact holes DH and GH are formed. A metal material or a transparent conductive material is patterned by a mask process to form a connection electrode () connecting the drain electrode SD of the switching thin film transistor ST and the gate electrode DG of the driving thin film transistor DT. (Fig. 9g)

A protective layer PAS is applied on the entire surface of the substrate SUB in which the thin film transistors ST and D are completed and the connection structure is formed. The passivation layer PAS is formed to protect the thin film transistors ST and DT, the connection electrode ), and various wires DL and VDD from the outside. The protective layer PAS is patterned to expose the openings PA. That is, the passivation layer PAS has the function of the bank BN defining the opening area at the same time. (Fig. 9h)

The organic light-emitting layer OL is applied on the entire surface of the substrate SUB on which the passivation layer PAS including the opening PA exposing the anode electrode ANO is formed. When the organic light-emitting layer OL is formed of a white organic light-emitting material, it may be applied to cover the entire surface of the substrate SUB. On the other hand, red, green, and blue organic light emitting materials may be applied by dividing each pixel. The cathode electrode CAT is formed by coating an opaque metallic material or a translucent conductive material on the entire surface of the substrate SUB on which the organic light emitting layer OL is formed. As a result, the organic light emitting diode OLE is formed in the opening region in which the anode electrode ANO, the organic light emitting layer OL, and the cathode electrode CAT are stacked. (Fig. 9i)

In the organic light emitting diode display according to the present invention, a black matrix and a color filter are first formed on a substrate. A thin film transistor and an organic light emitting diode are sequentially formed thereon. As a result, since the black matrix is disposed under the thin film transistor, it is possible to protect the channel region from light flowing from the bottom. Therefore, when forming a top-gate thin film transistor having a structure advantageous to an oxide semiconductor, it is not necessary to form a separate light shielding film.

In addition, the organic light emitting diode display according to the present invention is characterized in that an anode electrode is first formed on a substrate on which a black matrix and a color filter are formed. Accordingly, after the thin film transistor is formed, a function of a bank defining a light emitting region of the anode electrode may be given to the protective layer applied to protect the thin film transistor. As a result, there is an advantage in that the process of forming the bank and the mask can be removed.

It will be appreciated by those skilled in the art through the above description that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the present invention should not be limited to the content described in the detailed description, but should be defined by the claims.

DL: Data wiring SL: Scan wiring
VDD: drive current wiring ST: switching thin film transistor
DT: Driving thin film transistor OLE: Organic light emitting diode
CAT: cathode electrode (layer) ANO: anode electrode (layer)
BN: Bank (pattern) CF: Color filter
OLE: (white) organic light emitting layer SUB: substrate
PAS: protective film OC: overcoat layer
SG, DG: gate electrode SE: semiconductor layer
SS, DS: source electrode SD, DD: drain electrode
PH: pixel contact hole IL: intermediate insulating film

Claims (8)

A black matrix defining a light emitting area on the substrate;
A color filter formed in the light emitting area;
A buffer layer applied on the color filter;
A source electrode in which a transparent conductive material and a metal material are sequentially stacked on the buffer layer, a drain electrode facing the source electrode by a predetermined distance, and an oxide semiconductor material formed therebetween while in contact with the source electrode and the drain electrode. A thin film transistor including a semiconductor layer and a gate electrode overlapping a central region of the semiconductor layer with a gate insulating film therebetween;
An anode electrode formed by extending the drain electrode of the thin film transistor into the light emitting region and made of only the transparent conductive material;
An intermediate insulating film in contact with the gate electrode and the source region and the drain region of the semiconductor layer and covering the gate electrode and the semiconductor layer;
A passivation layer covering the intermediate insulating layer and the anode electrode and including an opening exposing the anode electrode corresponding to the emission region;
An organic light-emitting layer applied on the protective layer and stacked on the anode electrode at the opening; And
A cathode electrode applied on the organic light-emitting layer and stacked with the organic light-emitting layer at the opening,
The metal material is removed in a region of the source electrode that overlaps the source region of the semiconductor layer, and consists only of the transparent conductive material,
The source region of the semiconductor layer directly contacts an upper surface and a side surface of the transparent conductive material of the source electrode.
delete delete delete The method of claim 1,
The gate electrode and the gate insulating layer overlap only the central region of the semiconductor layer,
In the semiconductor layer, the source region and the drain region, which are conducted through plasma treatment using the gate electrode as a mask, and a channel region that is not conductive by overlapping with the gate electrode, are defined,
The organic light emitting diode display device includes a source region and a drain region of the semiconductor layer, and the gate electrode, respectively, in contact with the intermediate insulating layer.
Forming a black matrix defining a light emitting area on the substrate;
Forming a color filter filling the light emitting area;
Forming a buffer layer on the color filter;
A transparent conductive material and a metal material are continuously deposited on the buffer layer, patterned with a half-tone mask, and a source electrode of a thin film transistor in which a transparent conductive material and a metal material are stacked, and the thin film facing the source electrode by a predetermined distance Forming a drain electrode of a transistor and an anode electrode made of only the transparent conductive material and extending from the drain electrode to the light emitting region;
Forming a semiconductor layer of the thin film transistor using an oxide semiconductor material, connecting the source electrode and the drain electrode, and contacting top and side surfaces of the source electrode and the drain electrode;
Forming a gate electrode of the thin film transistor overlapping the central region of the semiconductor layer with a gate insulating layer therebetween;
Making a source region and a drain region of the semiconductor layer conductive through plasma treatment using the gate electrode as a mask, and defining a non-conducting channel region by overlapping the gate electrode;
Forming an intermediate insulating film in contact with the gate electrode and the source region and the drain region of the semiconductor layer and covering the gate electrode and the semiconductor layer;
Applying a protective layer to cover the anode electrode and the intermediate insulating layer, and forming an opening exposing the anode electrode to correspond to the light emitting area;
Applying an organic light emitting layer on the passivation layer so as to be stacked on the anode electrode at the opening; And
Including the step of applying a cathode electrode on the organic light-emitting layer,
The gate electrode and the gate insulating layer overlap only the central region of the semiconductor layer,
A source region and a drain region of the semiconductor layer and the gate electrode respectively contact the intermediate insulating layer,
The metal material is removed in a region of the source electrode that overlaps the source region of the semiconductor layer to consist of only the transparent conductive material,
The method of manufacturing an organic light emitting diode display, wherein the source region of the semiconductor layer directly contacts an upper surface and a side surface of the transparent conductive material of the source electrode. delete delete

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