KR100810630B1 - Organic Electroluminenscence Device and Fabricating Method of the same - Google Patents

Abstract

The present invention relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to convert an organic light emitting display device into an inverted structure including a first electrode (cathode) / EL / second electrode (anode). By simultaneously forming the first electrode when forming the source / drain electrodes, the organic light emitting device can reduce the manufacturing cost and simplify the process by reducing the number of process masks by omitting the via hole process and the first electrode forming step. And a method for producing the same.

Organic EL device, first electrode (cathode) / EL / second electrode (anode), mask reduction

Description

Organic electroluminescent device and its manufacturing method {Organic Electroluminenscence Device and Fabricating Method of the same}

1 is a cross-sectional view illustrating a conventional organic light emitting display device and a method of manufacturing the same.

2 is a cross-sectional view illustrating a top-emitting organic light emitting display device and a method of manufacturing the same according to the present invention.

<Description of the symbols for the main parts of the drawings>

300 substrate 310 semiconductor layer

320: gate insulating film 330: gate

340: interlayer insulating film 341: contact hole

345: source / drain electrode 350: first electrode

370: pixel definition layer (PDL) 380: organic layer

390: second electrode

The present invention relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to convert the organic light emitting display device into an inverted structure including a first electrode (cathode) / EL / second electrode (anode). An organic light emitting device and a method for manufacturing the same, which simultaneously form a first electrode when forming a source / drain electrode of the present invention.

Among flat panel display devices, organic electroluminescence devices (OLEDs) are self-luminous and have a wide viewing angle and a fast response time of 1 ms or less, thin thickness, low manufacturing cost, and high contrast. And other properties.

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

In general, an organic light emitting display device is divided into a passive matrix method and an active matrix method according to a method of driving N × M pixels arranged in a matrix form. The anode electrode and the cathode electrode are composed of a simple matrix-type device, which is easy to manufacture, but is limited to applications of low resolution and small displays due to problems such as resolution, increase in driving voltage, and deterioration of material life. On the other hand, in the active matrix method, the display area is equipped with a thin film transistor for each pixel to supply a stable current regardless of the number of pixels of the organic light emitting display device, thereby showing stable luminance and low power consumption, thereby applying high resolution and large display. It has the advantage of being advantageous.

In addition, the organic light emitting device is divided into a bottom emission type and a front emission type according to the direction in which the light emitted from the organic light emitting layer is emitted. The bottom emission type emits light toward the formed substrate, and a reflective electrode is formed on the organic light emitting layer. The transparent electrode is formed under the organic light emitting layer. In this case, when the organic light emitting diode adopts the active matrix method, the area where the thin film transistor is formed may not transmit light, thereby reducing the area where light can be emitted. On the other hand, in the front emission type, since a transparent electrode is formed on the organic light emitting layer and a reflective electrode is formed on the organic light emitting layer, light is emitted in a direction opposite to the substrate side, so that the light transmitting area is widened, so that the luminance can be improved. Can be.

1 is a cross-sectional view illustrating a conventional organic light emitting display device and a method of manufacturing the same.

Referring to FIG. 1, in the conventional organic light emitting display device, a buffer layer 105 is formed on a substrate 100.

After the semiconductor layer 110 including the source / drain regions 110c and 110a and the channel region 110b is stacked on the buffer layer 105, patterning is performed using a photoresist (PR) pattern as a first mask. It is formed.

A gate insulating layer 120 is formed over the entire surface of the semiconductor layer 110. After the metal material is stacked on the gate insulating layer 120 to correspond to the channel region 110b of the semiconductor layer 110, the gate electrode 130 is patterned using a second mask.

Impurities are implanted into the semiconductor layer 110 by using a third mask on the gate 130, so that the source / drain regions 110c and 110a and the source / drain regions 110c and 110a of the semiconductor layer 110 are formed. The channel region 110b interposed therebetween is defined.

Subsequently, an interlayer insulating layer 140 is formed on the entire surface of the substrate above the gate 130. A contact hole 141 that exposes the source / drain regions 110c and 110a of the semiconductor layer 110 through etching in the interlayer insulating layer 140 is opened using a fourth mask.

After the source / drain electrodes 145 are formed on the contact hole 141 and the interlayer insulating layer 140, source / drain regions 110c and 110a of the semiconductor layer 110 may be formed through etching using a fifth mask. The contacting source / drain electrodes 145 are patterned and formed.

The semiconductor layer 110, the gate 130, and the source / drain electrodes 145 form a thin film transistor.

Subsequently, a passivation film 150 is formed over the entire surface of the source / drain electrode 145, and a planarization film 160 is formed to planarize the substrate.

In the passivation layer 150 and the planarization layer 160, a via hole 165 exposing any one of the source / drain electrodes 145 is opened through etching using a sixth mask.

The first electrode 170 is stacked and patterned using a seventh mask to contact the source / drain electrode 145 through the via hole 165.

The first electrode 170 is an anode electrode and is formed of a transparent electrode such as indium tin oxide (ITO) or indium zinc oxide (IZO) having a high work function.

Subsequently, a pixel defining layer 175 having an opening that exposes a part of the surface of the first electrode over the entire substrate including the first electrode 170 is formed using an eighth mask.

An organic layer 180 including at least an organic light emitting layer 180c is formed on the first electrode 170 exposed in the opening. The organic layer 180 may include a hole injection layer 180a, a hole transport layer 180b, an electron transport layer 180d, and an electron injection layer 180e when the first electrode 170 is an anode in addition to the organic light emitting layer 180c. It may include one or more layers of the order consisting of.

Next, a second electrode 190 including the organic layer 180 is formed over the entire substrate. The second electrode 190 is a conductive metal having a low work function as a cathode and is formed of a reflective electrode having a thick thickness as one material selected from the group consisting of Mg, Ca, Al, Ag, and alloys thereof.

Conventional organic light emitting diodes are formed of a first electrode (anode) / EL / second electrode (cathode) structure. In this case, the process is complicated by performing an eight mask process, which increases the manufacturing process time and increases the material cost. Due to this, the manufacturing cost has a problem.

The technical problem to be achieved by the present invention is to solve the above-described problems of the prior art, the organic EL device is replaced by an inverted structure consisting of the first electrode (cathode) / EL / second electrode (anode) thin film By simultaneously forming the first electrode when forming the source / drain electrodes of the transistor, an organic field can be manufactured and the manufacturing cost can be simplified and the process can be simplified by reducing the number of process masks by eliminating the via hole process and the first electrode forming step. It is to provide a light emitting device and a method of manufacturing the same.

In order to achieve the above technical problem, the present invention

Board,

A thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode formed on the substrate, and a first electrode formed on the same layer as the source / drain electrode and having a thickness smaller than that of the source / drain electrode,

A pixel definition layer formed on the source / drain electrodes and the first electrode and exposing a part of the surface of the first electrode;

An organic film layer formed on the exposed first electrode and including an organic light emitting layer, and

A second electrode formed on the organic layer;
The source / drain electrodes are one type of structure selected from the group consisting of Mo / Al / Mo, MoW / Al / MoW, MoW / Al-Nd / MoW, Ti / Al-Nd / Ti, and Ti / Al / Ti. The first electrode provides an organic light emitting display device, characterized in that one structure selected from the group consisting of Mo / Al, MoW / Al, MoW / Al-Nd, Ti / Al-Nd, and Ti / Al. do.

In addition, the present invention

Providing a substrate,

Forming a thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode on the substrate, and simultaneously forming a first electrode having a thickness thinner than that of the source / drain electrode when the source / drain electrode is formed;

Forming a pixel defining layer exposing a portion of the surface of the first electrode on the source / drain electrode and the first electrode,

Forming an organic film layer including an organic light emitting layer on the exposed first electrode, and forming a second electrode on the organic film layer,
The source / drain electrodes are one type of structure selected from the group consisting of Mo / Al / Mo, MoW / Al / MoW, MoW / Al-Nd / MoW, Ti / Al-Nd / Ti, and Ti / Al / Ti. The first electrode is manufactured of an organic light emitting display device, characterized in that one structure selected from the group consisting of Mo / Al, MoW / Al, MoW / Al-Nd, Ti / Al-Nd, and Ti / Al. It is also achieved by the method.

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

2 is a cross-sectional view illustrating a top-emitting organic light emitting display device and a method of manufacturing the same according to the present invention.

Referring to FIG. 2, the organic light emitting display device of the present invention may further include a buffer layer 305 on the substrate 300. The substrate 300 is a transparent insulating substrate such as glass, plastic, or quartz. The buffer layer 305 is formed on the substrate 300 to protect the thin film transistor formed in a subsequent process from impurities flowing out of the substrate. The buffer layer 305 is not necessarily stacked, but may be formed of a silicon oxide film, a silicon nitride film, or a double layer in which the buffer layer 305 is stacked. The buffer layer 305 is It is formed by performing a method such as plasma chemical vapor deposition (PECVD) or low pressure chemical vapor deposition (LPCVD).

Subsequently, the semiconductor layer 310 including the source / drain regions 310c and 310a and the channel region 310b is formed on the buffer layer 305 by patterning the first mask.

 The semiconductor layer 310 may be formed of amorphous silicon or polysilicon, but is preferably formed of polysilicon. The semiconductor layer 310 is formed by depositing amorphous silicon using a chemical vapor deposition (CVD) method, crystallizing a polysilicon film using a crystallization method, and then patterning the amorphous silicon. The CVD method may use a chemical vapor deposition method such as PECVD, LPCVD. At this time, when the amorphous silicon is carried out by PECVD, a process of lowering the concentration of hydrogen by dehydrogenation by heat treatment after deposition of a silicon film is performed.

In addition, the crystallization method of the amorphous silicon film may be RTA (Rapid Thermal Annealing) process, SPC (Solid Phase Crystallization), ELA (Excimer Laser Crystallization), MIC (Metal Induced Crystallization), MILC (Metal Induced Lateral Crystallization) or Any one or more of the SLS method (Sequential Lateral Solidification) can be used.

The gate insulating layer 320 is formed over the entire substrate including the semiconductor layer 310. The gate insulating layer 320 is formed of a silicon oxide film, a silicon nitride film, or a double layer thereof, and stacked by performing a method such as PECVD or LPCVD.

A gate electrode 330 corresponding to a predetermined region of the semiconductor layer 310 is patterned on the gate insulating layer 320 by using a second mask. When the gate electrode 330 is formed of a polysilicon film, amorphous silicon or polysilicon is used, and the gate electrode 330 is formed in the same manner as the method of forming the semiconductor layer 310, and molybdenum (Mo), tungsten (W), and tungsten molybdenum are formed. (MoW), tungsten silicide (WSix), aluminum (Al), etc., when formed in one kind selected from the group consisting of a vacuum deposition method or sputtering method using a second mask after lamination is formed by patterning.

Subsequently, an impurity is implanted into the semiconductor layer 310 by using a third mask over the gate 330, thereby forming source / drain regions 310c and 310a in the semiconductor layer 310. A channel region 310b is defined between the source / drain regions 310c and 310a.

The impurity may be selected from n-type or p-type. The n-type impurity is formed of one selected from the group consisting of phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The p-type impurity is formed of one selected from the group consisting of boron (B), aluminum (Al), gallium (Ga), and indium (In).

Subsequently, an interlayer insulating layer 340 is formed over the entire substrate on the gate 330. The interlayer insulating film 340 may be formed of a silicon oxide film, a silicon nitride film, or a double layer thereof, and may be stacked by performing a method such as PECVD or LPCVD.

Subsequently, contact holes 341 that expose the source / drain regions 310c and 310a, respectively, are opened in the interlayer insulating layer 340 through etching using a fourth mask.

A metal layer is stacked on the source / drain regions 310c and 310a and the interlayer insulating layer 340 exposed in the contact holes 341, and then patterned by etching using a fifth mask to pattern the source layer. The drain electrodes 345 and the first electrode 350 are formed at the same time.

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The source / drain electrodes 345 are formed of MoW, Al or Al alloy, Ti, or the like, which are low resistance materials, in order to reduce wiring resistance, and they are formed in a two-layer or more multilayer structure. It is preferably formed of a triple layer, wherein the triple layer has a structure such as Mo / Al / Mo, MoW / Al / MoW, MoW / Al-Nd / MoW, Ti / Al-Nd / Ti or Ti / Al / Ti. It can be formed into one selected.

In the present invention, the source / drain electrodes 345 may be formed of a triple layer having a Mo / Al / Mo structure.

The source / drain electrodes 345 are formed to have a thickness of 4000 ns to 11000 ns. In the source / drain electrodes 345, the upper and lower Mos are formed at 500 kPa to 2000 kPa and Al is formed at 3000 kPa to 7000 kPa.

When the thickness of Mo formed on the upper and lower portions of the source / drain electrodes 345 is 500 kΩ or less, Al may be revealed when the source / drain electrodes are patterned, and a galvanic phenomenon may occur. By Mo having a specific resistance, the wiring resistance value increases, the material cost increases, and the manufacturing process time becomes long. In addition, when the thickness of Al is less than 3000 GPa, a problem may occur due to an increase in the wiring resistance of the source / drain electrode 345. When the thickness of Al is more than 7000 GPa, the device becomes thick, the material cost increases, and the manufacturing process time increases. It will be longer.

Preferably, the source / drain electrodes 345 are formed to have a thickness of 4000 kPa to 6000 kPa. If the thickness of the source / drain electrodes 345 is less than or equal to 4000 kV, a problem may occur in the wiring resistance.

The source / drain electrodes 345 are deposited by sputtering or vacuum deposition.

In this case, the semiconductor layer 310, the gate electrode 330, and the source / drain electrode 345 are components constituting the thin film transistor.

In addition, when the source / drain electrode 345 is formed, the first electrode 350 simultaneously formed on the same layer is formed as a single layer or a double layer of the source / drain electrode 345. In this case, the single layer or the double layer is formed of one or two selected from the same material as the source / drain electrode 345 material.
In this case, when the first electrode 350 is formed of a double layer, the first electrode 350 should be selected in consideration of a work function. In this case, since the first electrode 350 may be formed of two kinds selected from the same material as the source / drain electrode, Mo / Al, MoW / Al, MoW / Al-Nd, Ti / Al-Nd, and Ti It is formed of any one kind of structure selected from the group consisting of / Al. Preferably, the first electrode 350 has a Mo / Al structure.
The reason for this structure is that when the upper portion of the first electrode 350 is Mo, MoW or Ti, their work function is high and the difference in work function with the second electrode formed as the anode electrode in a subsequent process becomes small. Electron-hole flow is not smooth. In addition, when the first electrode is formed of only Al, a defect due to a galvanic phenomenon may occur when patterning the source / drain electrode 345. On the other hand, when the first electrode 350 is formed in a double layer structure having an upper portion of Al, since the work function of Al formed on the upper portion is low, the work function is corrected to form the second electrode as an anode electrode in a subsequent process. Hole flow is smooth.

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Therefore, when the source / drain electrodes 345 and the first electrodes 350 are formed to have the same thickness with the same structure, a problem occurs in the work function with the second electrode due to the work function of the metal formed thereon. Since the luminous efficiency is lowered, the upper metal of the first electrode is not formed, and therefore, the light emitting efficiency is lower than the source / drain electrode thickness.

For this reason, the first electrode 350 is formed to a thickness of 3500 kPa to 9000 kPa. At this time, Mo is formed from 500 kPa to 2000 kPa, and Al is formed from 3000 kPa to 7000 kPa.

When the thickness of the Mo formed on the lower portion of the first electrode 350 is 500 kΩ or less, Al may be exposed when the source / drain electrode is patterned, and a galvanic phenomenon may occur. Since Mo increases the wiring resistance, it is difficult to match the work function. In addition, when the thickness of Al is less than or equal to 3000 kW, a problem may occur in the work function due to an increase in wiring resistance. When the thickness of Al is greater than or equal to 7000 mW, the device becomes thick, the material cost increases, and the manufacturing process time becomes long.

Preferably, the first electrode 350 is formed to a thickness of 3500 ~ 5500Å. When the thickness of the first electrode 350 is less than or equal to 3500 mW, a problem may occur in wiring resistance. When the thickness of the first electrode 350 is greater than or equal to 5500 mW, Mo, MoW, or Ti is positioned on the first electrode. The luminous efficiency of the EL can be lowered.

When forming the source / drain electrodes 345, the first electrode 350 is stacked in the order of Mo, Al, and Mo by sputtering or vacuum deposition, and then, to the region where the first electrode is to be formed by using a fifth mask. The source / drain electrodes 345 are patterned. Thereafter, the first electrode 350 having a Mo / Al structure is formed by etching the upper Mo of the region where the first electrode is to be formed using the sixth mask.

As a result, the formation of the first electrode 350, which is the cathode of the present invention, is simultaneously formed on the same layer as the source / drain electrode 345, thereby eliminating the conventional via hole process and the first electrode forming process, thereby reducing the number of masks. can do. In addition, by forming the thickness of the first electrode 350 to 3500 to 5500 Å, it is possible to prevent the decrease in the luminous efficiency of the EL by correcting the work function with the anode electrode which is the second electrode in the subsequent process.

Subsequently, a pixel definition layer 370 having an opening that exposes a portion of the surface of the cathode electrode 350 is stacked over the entire surface of the source / drain electrode 345 and the first electrode 350, and then the seventh is formed. Formed by etching using a mask.

The pixel defining layer 370 may use an organic or inorganic type, and the organic type may be selected from the group consisting of polyimide (PI), polyamide (PA), acrylic resin, benzocyclobutene (BCB) or phenol resin. It is made of a species, and is formed of SiO 2 in the inorganic system. The pixel definition layer 370 is formed through spin coating.

Next, an organic layer 380 including at least an organic light emitting layer 380c is formed on the cathode electrode 350 exposed in the opening. The organic layer 380 may include an electron injection layer (EIL) 380a, an electron transport layer (ETL) 380b, and an organic layer besides the organic emission layer (EML) 380c. The light emitting layer (EML) 380c, hole transport layer (HTL; Hole Transort Layer (380d), hole injection layer (HIL) (Hole Injection Layer) (380e) may further comprise one or more layers of the order.

The organic light emitting layer may be a low molecular material or a high molecular material.

The low molecular weight material is formed of one selected from the group consisting of aluminy chinolium complex (Alq3), anthracene (Anthracene), cyclopentadiene (Cyclo pentadiene), BeBq2, ZnPBO, Balq, DPVBi, BSA-2 and 2PSP . Preferably, the organic light emitting layer is formed of an aluminy chinolium composite (Alq3). The polymer material is poly (p-phenylenevinylene) (PPV; poly (p-phenylenevinylene)) and its derivatives, polythiophene (PT) and its derivatives and polyphenylene (PPP; polyphenylene) and its derivatives It is formed of one selected from the group consisting of.

The organic layer 380 is deposited by vacuum deposition, spin coating, inkjet printing, or laser induced thermal imaging (LITI). In addition, the patterning of the organic layer 380 may be implemented using laser thermal transfer, vacuum deposition using a shadow mask, or the like.

Subsequently, a second electrode 390 including the organic layer 380 is formed over the entire substrate. The second electrode 390 is formed as an anode electrode, is formed as a transparent electrode having a high work function, and is formed by a vacuum deposition method. Preferably, the transparent electrode is formed of ITO or IZO.

Subsequently, the substrate formed up to the second electrode 390 is bonded to the encapsulation substrate, thereby completing a top emission organic light emitting diode having a first electrode (cathode) / EL / second electrode (anode) structure having a seven mask process. .

In the present invention, a thin film transistor including a top gate type in which a gate electrode is formed on a semiconductor layer has been described. However, the present invention is not limited thereto. For example, the gate electrode is disposed below the semiconductor layer. The present invention also applies to a thin film transistor including a bottom gate type.

As described above, according to the present invention, the organic light emitting diode is converted into an inverted structure including a first electrode (cathode) / EL / second electrode (anode) to form a first electrode when forming a source / drain electrode of a thin film transistor. By simultaneously forming, the manufacturing cost can be reduced due to the reduction of the number of process masks by omitting the via hole process and the first electrode forming step.

Claims (27)

Board; A thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode formed on the substrate, and a first electrode formed on the same layer as the source / drain electrode and having a thickness thinner than that of the source / drain electrode; A pixel definition layer formed on the source / drain electrode and the first electrode and exposing a part of the surface of the first electrode; An organic layer formed on the exposed first electrode and including an organic light emitting layer; And A second electrode formed on the organic layer; The source / drain electrodes are one type of structure selected from the group consisting of Mo / Al / Mo, MoW / Al / MoW, MoW / Al-Nd / MoW, Ti / Al-Nd / Ti, and Ti / Al / Ti. And the first electrode is made of Mo / Al or MoW / Al. delete delete delete delete delete The method of claim 1, The organic light emitting device of claim 1, wherein the first electrode has a thickness of 3500 kPa to 9000 kPa. The method of claim 7, wherein The organic light emitting device of claim 1, wherein the first electrode has a thickness of 3500 kPa to 5500 kPa. The method of claim 1, The thickness of the Mo used for the first electrode is 500 kPa to 2000 kPa, and the thickness of Al is 3000 kPa to 7000 kPa. The method of claim 1, The source / drain electrode has a thickness of 4000 kPa to 11000 kPa. The method of claim 10, The source / drain electrode has a thickness of 4000 kPa to 6000 kPa. The method according to claim 1 or 10, The thickness of the upper and lower Mo used for the source / drain electrodes is 500 kPa to 2000 kPa, and the thickness of Al is 3000 kPa to 7000 kPa. The method of claim 1, The second electrode is an organic light emitting device, characterized in that the transparent electrode made of ITO or IZO. Providing a substrate; Forming a thin film transistor including a semiconductor layer, a gate electrode, and a source / drain electrode on the substrate, and simultaneously forming a first electrode having a thickness thinner than the source / drain electrode on the same layer as the source / drain electrode; Forming a pixel definition layer on the source / drain electrode and the first electrode to expose a portion of the surface of the first electrode; Forming an organic layer including an organic light emitting layer on the exposed first electrode; And Forming a second electrode on the organic layer; The source / drain electrodes are one type of structure selected from the group consisting of Mo / Al / Mo, MoW / Al / MoW, MoW / Al-Nd / MoW, Ti / Al-Nd / Ti, and Ti / Al / Ti. The first electrode is made of Mo / Al or MoW / Al. delete delete delete delete delete The method of claim 14, The thickness of the first electrode is 3500 9000 to 9000 Å manufacturing method of an organic light emitting device. The method of claim 20, The first electrode has a thickness of 3500 kPa to 5500 kPa, the manufacturing method of the organic light emitting device. The method of claim 14 or 20, The thickness of the Mo used for the first electrode is 500 kPa to 2000 kPa, and the thickness of Al is 3000 kPa to 7000 kPa. The method of claim 14, The source / drain electrode has a thickness of 4000 kPa to 11000 kPa. The method of claim 23, The source / drain electrode has a thickness of 4000 kPa to 6000 kPa. The method of claim 14 or 23, The thickness of the upper and lower Mo used for the source / drain electrodes is 500 kPa to 2000 kPa, and the thickness of Al is 3000 kPa to 7000 kPa. The method of claim 14, And the first electrode and the source / drain electrode are formed by a sputtering method. The method of claim 14, The second electrode is a method of manufacturing an organic light emitting display device, characterized in that the transparent electrode made of ITO or IZO.

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