KR20080060025A - Organic light emitting display and method for fabricating the same - Google Patents

Abstract

An organic light emitting display and a method for fabricating the same are provided to prevent damage of pads due to an etchant used for etching a contact electrode by forming the contact electrode with the other photomask after forming the pads with one photomask. A method for fabricating an organic light emitting display includes the steps of: forming signal lines including a gate line(310a) and a data line(335d) on a first substrate(300); forming at least one thin film transistor including a gate electrode(310b), a semiconductor layer(330), a source electrode(335a), and a drain electrode(335b) in a region defined by the signal lines; forming at least one insulating layer(325,340) on the signal lines and the thin film transistor; forming a first via hole(345a) to expose one ends of the signal lines and a second via hole(345b) to expose a part of the drain electrode, inside the insulating layers; stacking a first conductive layer on the first substrate including the first and second via holes; forming a first photomask(355) on the first conductive layer corresponding to the first via hole; forming pads(350a,350b) electrically connected to one ends of the signal lines through the first via hole by etching the first conductive layer with the first photomask; forming a second conductive layer(360) on the first substrate including the first photomask; forming a second photomask on the second conductive layer corresponding to the second via hole; forming a contact electrode electrically connected to the drain electrode by etching the second conductive layer with the second photomask; and removing the first and second photomasks.

Description

Organic light Emitting Display and method for fabricating the same

1 is a photograph showing damage to a pad manufactured according to a conventional method for manufacturing an organic light emitting display device.

2 is a photograph showing a peeling phenomenon of a contact electrode manufactured according to a conventional method of manufacturing an organic light emitting display device.

3A is a plan view illustrating an organic light emitting display device according to an embodiment of the present invention.

3B is a cross-sectional view of an organic light emitting panel according to an embodiment of the present invention, cut along the line II ′ of FIG. 3A.

4A to 4H are cross-sectional views illustrating processes for describing a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

200: first substrate 210a: gate line

210b; Gate electrode 225: first insulating layer

230: semiconductor layers 235a and 235b: source / drain electrodes

235d: data line 240: second insulating layer

250: first conductive layer 250a, 250b: gate / data pad

260a: contact electrode 270: second substrate

275: first electrode 280: bank layer

285a: contact spacer 285b: partition wall

290: organic light emitting layer 295: second electrode

Among flat panel displays, an organic light emitting display device is a self-luminous display device which electrically excites organic compounds to emit light. The organic light emitting display device does not need a backlight used in the LCD, so it is not only lightweight but also simplifies the process. In addition, low-temperature fabrication is possible, response speed is 1ms or less, high speed response speed, low power consumption, wide viewing angle, high contrast and the like.

The organic light emitting display device includes an organic light emitting layer between the anode and the cathode, and holes supplied from the anode and electrons received from the cathode combine in the organic light emitting layer to form an exciton, which is a hole-electron pair, and then the exciton is in a ground state. The light emitted by the energy generated by returning to.

In general, an organic light emitting display device is manufactured by forming thin film transistors on a substrate, forming a light emitting diode electrically connected to the thin film transistors, and then bonding the substrate and the encapsulation substrate together. However, in this case, even if the thin film transistors are formed satisfactorily, when a failure occurs in the light emitting diode, the organic light emitting display device is determined to be a failure. That is, since the yield of the light emitting diode determines the overall yield, there is a problem in that process time and manufacturing cost are wasted. Therefore, in order to solve this problem, an organic light emitting display device is manufactured by manufacturing a first substrate, which is a TFT array substrate on which thin film transistors are formed, and then fabricating a second substrate on which light emitting diodes are formed.

The first substrate, which is a TFT array substrate, is formed with a display unit, a driver unit for applying a drive signal to the display unit, and a pad unit connected to the display unit and the driver unit to transfer the drive signal to the display unit.

The display unit is positioned in a region defined by signal lines and signal lines including gate lines, data lines, and power lines, and includes a plurality of subpixels including one or more thin film transistors and a capacitor.

The pad unit may include a gate pad and a data pad connected to one end of a gate line or a data line.

In this case, the drain electrode of the thin film transistor positioned on the subpixel is connected to the light emitting diode formed on the second substrate and needs a contact electrode for supplying a driving current.

Conventionally, a pad conductive layer is laminated by using indium tin oxide (ITO), and patterned to form a pad, and then a metal layer such as molybdenum is laminated on the substrate including the pad and patterned to form a contact electrode. Formed. However, when the pad and the contact electrode are formed as described above, the pad is exposed to an etchant for etching the metal layer for the contact electrode, thereby causing the pad to be damaged as illustrated in FIG. 1.

In addition, in order to prevent this, when the contact electrode is first formed and then the pad is formed, the contact electrode is exposed to an etchant used for etching the conductive layer, thereby causing a phenomenon in which the contact electrode is peeled.

This damages the pad and the contact electrode, so that the signal applied from the driver cannot be accurately applied to the subpixel, thereby reducing the screen quality and reducing the reliability of the device.

Accordingly, an object of the present invention is to provide an organic light emitting display device having improved screen quality and device reliability.

In order to achieve the above object, the present invention comprises the steps of forming a signal line including a gate line and a data line on the first substrate; Forming at least one thin film transistor including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode in a region defined by the signal lines; Forming at least one insulating layer on the signal lines and the thin film transistor; Forming a first via hole exposing one end of the signal lines and a second via hole exposing a portion of the drain electrode in the insulating layer; Stacking a first conductive layer on a first substrate including the first and second via holes; Forming a first photomask on a first conductive layer corresponding to the first via hole; Etching the first conductive layer using the first photomask to form pads electrically connected to one end of the signal lines through the first via hole; Forming a second conductive layer on the first substrate including the first photomask; Forming a second photomask on a second conductive layer region corresponding to the second via hole; Forming a contact electrode electrically connected to the drain electrode by etching the second conductive layer using the second photomask; And it provides a method of manufacturing an organic light emitting display device comprising the step of removing the first and second photomask.

In addition, the present invention, the first substrate; Signal lines on the first substrate and including a gate line and a data line; A plurality of subpixels positioned on an area defined by the signal lines and including a thin film transistor including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode; A plurality of pads electrically connected to one end of the signal lines to transmit a driving signal to the subpixels; And a contact electrode connected to the drain electrode, wherein the pads have a thickness of about 50 to about 500 microns.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3A is a plan view of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 3A, an organic light emitting display device according to an exemplary embodiment of the present invention may include a display unit P and a driver for applying a driving signal to the display unit P on the first substrate 200. The pad unit is connected to the display unit P and the driving unit to include a gate pad 250a and a data pad 250b for transmitting a driving signal to the display unit P.

The display unit P includes a plurality of subpixels S, and each subpixel S is positioned in a region defined by signal lines including a gate line 210a, a data line 235d, and a power line. . Each subpixel S includes at least one thin film transistor, a capacitor, and a light emitting diode.

3B is a cross-sectional view taken along the line II ′ of FIG. 3A. Hereinafter, a configuration of an organic light emitting display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 3B.

Referring to FIG. 3B, in the organic light emitting display device according to an exemplary embodiment, signal lines including a gate line 210a, a data line 235d, and the like are positioned on a first substrate 200. The subpixel S area is defined by the intersection of these. Each subpixel S includes a semiconductor layer 230, a gate electrode 210b corresponding to a predetermined region of the semiconductor layer 230, and a gate insulating layer 225 positioned between the semiconductor layer 230 and the gate electrode 210b. And at least one thin film transistor T including a source electrode 235a and a drain electrode 235b electrically connected to the semiconductor layer 230. Each subpixel S stores a data signal applied by the data line 235d and includes one or more capacitors Cst including the first storage electrode 210c and the second storage electrode 235c. do.

Here, a contact electrode 260a electrically connected to the drain electrode 235b is positioned on the drain electrode 235b of the thin film transistor T. The contact electrode 260a may include a metal such as molybdenum, and the thickness of the contact electrode 260a may be 1500 to 5000 mm 3.

In order to transfer driving signals to the subpixels S, pads 250a may be electrically connected to one end of signal lines including a gate line 210a and a data line 235d on one side of the first substrate 200. , 250b). The pads may include a gate pad 250a and a data pad 250b. The pads 250a and 250b may include a transparent conductive material such as indium tin dioxide (ITO), and may have a thickness of 50 to 500 kPa.

The second substrate 270 is positioned to face the first substrate 200. A first electrode 275 is positioned on the second substrate 270, and a bank layer 280 including an opening 277 exposing a portion of the first electrode 275 is positioned on the first electrode 275. do. Contact spacers 285a and barrier ribs 285b are disposed on a portion of the bank layer 280, and an organic light emitting layer 290 is disposed in the opening 277.

On the organic light emitting layer 290 and the contact spacer 280a, a second electrode 295 patterned by the partition 285b is positioned.

The second electrode 295 and the contact electrode 260a formed on the contact spacer 280a by the bonding of the first substrate 200 and the second substrate 270 are electrically connected to each other, so that the thin film transistor T The generated driving current is transferred from the drain electrode 235b to the second electrode 295.

Here, the first electrode 275 may be an anode, and the second electrode 295 may be a cathode.

Hereinafter, a method of manufacturing an organic light emitting display device according to an embodiment of the present invention will be described with reference to FIGS. 4A to 4I. Here, reference numeral S denotes a subpixel area.

Referring to FIG. 4A, a first metal layer is formed on the first substrate 300 and then patterned to form a gate line 310a, a gate electrode 310b, and a first storage electrode 310c. Next, a first insulating layer 325 is formed on the first substrate 300 including the gate line 310a, the gate electrode 310b, and the first storage electrode 310c.

The first substrate 300 may be made of glass, plastic, or metal, and the gate line 310a may be formed of aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), molybdenum alloy (Mo alloy), tungsten, or the like. It may include a metal. The first insulating layer 325 may be formed of a silicon oxide film or a silicon nitride film.

The semiconductor layer 330 is formed on the region of the first insulating layer 325 corresponding to the gate electrode 310b. The semiconductor layer 330 may be formed using amorphous silicon or polysilicon.

Referring to FIG. 4B, a second metal layer is coated on the first insulating layer 325 including the semiconductor layer 330, and then patterned to form a source electrode 335a electrically connected to the semiconductor layer 330. The drain electrode 335b is formed, and the second storage electrode 335c is formed on the region of the first insulating layer 325 corresponding to the first storage electrode 310c. The data line 335d is formed on a predetermined region of the first insulating layer 325. Here, the second metal layer may use low resistance magnesium (Mg), silver (Ag), aluminum (Al), calcium (Ca), molybdenum (Mo), or an alloy thereof.

Here, the source electrode 335a is formed in an annular shape or a U shape to increase the length of the channel region of the semiconductor layer 330, and the drain electrode 335b is positioned in the center portion of the annular shape or the U shape. Can be formed.

Next, the first insulating layer 325 and the second insulating layer 340 are etched to expose a portion of the first via hole 345a exposing a portion of the gate line 310a and a portion of the drain electrode 335b. The third via hole 345c exposing the second via hole 345b and a part of the data line 335d is formed.

Referring to FIG. 4C, a first conductive layer is formed on the first substrate 300 including the first to third via holes 345a, 345b, and 345c. The first conductive layer may be formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). Then, a photoresist is applied on the first conductive layer 350, and the photoresist is exposed and developed to cover the first conductive layer 350 corresponding to the first and third via holes 345a and 345c. The first photomask 355 is formed. Here, the thickness of the first conductive layer 350 may be formed to 50 to 500Å. If the thickness of the first conductive layer 350 is 50 GPa or more, the thickness uniformity of the first conductive layer 350 can be ensured in the process, and the resistance enough to receive an electrical signal from the gate line 310a. Will have When the thickness of the first conductive layer 350 is 500 mm or less, the residue of the first conductive layer does not remain on another region after the first conductive layer 350 is patterned.

Conventionally, when the pads 350a and 350b and the contact electrode 360a are formed, the first conductive layer and the second conductive layer are stacked and then patterned at the same time, so that the first conductive layer is an etchant of the second conductive layer. Since it is etched by to form it to the desired thickness or more, the thickness due to the damage of the etchant had to be compensated. Accordingly, since the first conductive layer had to be laminated thickly, the lamination time and the cost used for the material increased. In addition, the first conductive layer is formed in the entire region of the first substrate 300, and then, except for a predetermined region, all of them must be removed. At this time, if the thickness of the metal layer is thick, residues remain in other regions. There was also a problem of fouling.

However, the organic light emitting display device according to the exemplary embodiment of the present invention can be stacked to a required thickness because there is no damage caused by the etchant used to form the contact electrode when the pads 350a and 350b are formed. This can reduce manufacturing costs. When the metal layer is patterned, no residue remains on other portions, and the quality of the pattern may be improved.

Referring to FIG. 4D, the first conductive layer is etched using the first photomask 355 to form the gate pad 350a and the data pad 350b. Next, a second conductive layer 360 is formed on the second insulating layer 340 including the first photomask 355 and the second via hole 345b. Here, the second conductive layer 360 may include a metal such as molybdenum.

Referring to FIG. 4E, a photoresist is applied on the second conductive layer 360, and the photoresist is exposed and developed to form a second photomask 365 on the region of the second conductive layer 360 corresponding to the second via hole 345b. ).

Referring to FIG. 4F, the second conductive layer is etched using the second photomask 365 to form a contact electrode 360a electrically connected to the drain electrode 335b, and as shown in FIG. 4G. The first photomask 355 and the second photomask 365 are removed by ashing or stripping at once. In this case, the thickness of the contact electrode 360a may be formed to be 1500 to 5000 mW to reduce the resistance and secure the step coverage.

Conventionally, when the pads 350a and 350b and the contact electrode 360a are formed, the first conductive layer and the second conductive layer are stacked and then patterned at the same time, so that the second conductive layer is too thick. There was a problem that the first conductive layer is more severely damaged due to the over etch of the conductive layer. However, in the present invention, since the first photomask 355 protects the formed pads 350a and 350b, the pads 350a and 350b may be formed thicker than the conventional one in consideration of the resistance and the step coverage of the contact electrode 360a. 350b) is not damaged.

Referring to FIG. 4H, a second substrate 370 is prepared. The second substrate 370 may include transparent glass and plastic. The first electrode 375 is formed on the prepared second substrate 370. The first electrode 375 may be an anode, and is formed as a common electrode using a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). do. Next, a bank layer 380 including an opening 377 exposing a part of the first electrode 375 is formed on the first electrode 375. The bank layer 380 may be formed of an organic layer such as polyimide, benzocyclobutene, and polyacryl resin.

Next, a forward tapered contact spacer 385a and a reverse tapered partition 385b are formed on a portion of the bank layer 380.

In addition, the organic light emitting layer 390 is formed in the opening 385, and the second electrode 395 is formed on the organic light emitting layer 390 and the contact spacer 385a to be patterned for each subpixel by the partition 385b. .

Referring to FIG. 4I, the second substrate 370 manufactured as described above is bonded to the first substrate 300. At this time, the contact electrode 360a of the first substrate 300 and the second electrode 395 positioned on the contact spacer 385a of the second substrate 370 are bonded to each other. As a result, the driving current generated from the thin film transistor T of the first substrate 300 is transferred to the second electrode 395 of the second substrate 370, and the organic light emitting layer 390 emits light corresponding thereto. .

In the exemplary embodiment of the present invention, the pads 350a and 350b are first formed using the first photomask 355 and then the contact electrode 360a is formed using the second photomask 365. The order is not limited thereto, and the contact electrode 360a may be formed first.

As described above, the organic light emitting display device according to the exemplary embodiment of the present invention forms the pads 350a and 350b by using a photomask and then does not remove the contact electrodes 360a by using another photomask. ), The pads 350a and 350b are prevented from being damaged by the etchant used to etch the contact electrode 360a.

Accordingly, the organic light emitting display device according to an embodiment of the present invention can improve the reliability of the device by preventing the pads 350a and 350b from being damaged or the peeling of the contact electrode 360a.

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

As described above, the present invention can improve the reliability of the device and can reduce the manufacturing cost. In addition, the present invention has the effect of improving the quality of the screen.

Claims (13)

Forming signal lines including a gate line and a data line on the first substrate; Forming at least one thin film transistor including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode in a region defined by the signal lines; Forming at least one insulating layer on the signal lines and the thin film transistor; Forming a first via hole exposing one end of the signal lines and a second via hole exposing a portion of the drain electrode in the insulating layer; Stacking a first conductive layer on a first substrate including the first and second via holes; Forming a first photomask on a first conductive layer corresponding to the first via hole; Etching the first conductive layer using the first photomask to form pads electrically connected to one end of the signal lines through the first via hole; Forming a second conductive layer on the first substrate including the first photomask; Forming a second photomask on a second conductive layer region corresponding to the second via hole; Forming a contact electrode electrically connected to the drain electrode by etching the second conductive layer using the second photomask; And A method of manufacturing an organic light emitting display device, the method comprising removing the first and second photomasks. The method of claim 1, The first conductive layer and the second conductive layer of the organic light emitting display device comprising a different material. The method of claim 2, The first conductive layer includes a transparent conductive material, and the second conductive layer includes molybdenum. The method of claim 1, And the first conductive layer is formed to a thickness of 50 to 500 GPa. The method of claim 1, And the second conductive layer is formed to a thickness of 1500 to 5000 GPa. The method of claim 1, Providing a second substrate facing the first substrate; Forming a first electrode on the second substrate; Forming a bank layer on the first electrode, the bank layer including an opening exposing a portion of the first electrode; Forming a forward tapered contact spacer and an inverse tapered partition on a portion of the bank layer; Forming an organic light emitting layer in the opening; Forming a second electrode on the organic light emitting layer and the contact spacer; And And bonding the first substrate and the second substrate to each other such that the second electrode and the contact electrode on the contact spacer are electrically connected to each other. The method of claim 6, The first electrode is an anode including a transparent conductive material, and the second electrode is a cathode. A first substrate; Signal lines on the first substrate and including a gate line and a data line; A plurality of subpixels positioned on an area defined by the signal lines and including a thin film transistor including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode; A plurality of pads electrically connected to one end of the signal lines to transmit a driving signal to the subpixels; And A contact electrode connected to the drain electrode, The pad of the organic light emitting display device having a thickness of 50 to 500Å. The method of claim 8, The pad and the contact electrode may include different materials. The method of claim 8, The pad includes a transparent conductive material, and the contact electrode includes molybdenum. The method of claim 8, The thickness of the contact electrode is 1500 to 5000Å organic light emitting display device. The method of claim 8, A second substrate facing the first substrate; A first electrode on the second substrate; A bank layer on the second substrate including the first electrode, the bank layer including an opening exposing a portion of the first electrode; A forward tapered contact spacer and an inverse tapered partition wall disposed on the bank layer; An organic light emitting layer positioned in the opening; And And a second electrode disposed on the organic light emitting layer and the contact spacer and patterned by the partition wall. And a second electrode on the contact spacer and the contact electrode are electrically connected. The method of claim 12, The first electrode is an anode, and the second electrode is a cathode.

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