KR102139677B1 - Flexible organic electroluminescent device and method for fabricating the same - Google Patents

Abstract

The present invention relates to a flexible organic light emitting device and a manufacturing method thereof, the disclosed invention is a substrate having a display area including a plurality of pixel areas and a non-display area including a pad area outside thereof is defined; A polyimide layer formed on the substrate; A low resistance inorganic film formed on the polyimide layer and conducting electricity; A buffer layer formed on the low-resistance inorganic film; A plurality of thin film transistors formed in each pixel region on the buffer layer; An interlayer insulating film and a planarization film stacked on the display area and the non-display area of the substrate including the thin film transistor; An organic light emitting element formed in each pixel region on the planarization layer and electrically connected to the thin film transistor; And a protective film covering the organic light emitting device.

Description

Flexible organic light emitting device and its manufacturing method {FLEXIBLE ORGANIC ELECTROLUMINESCENT DEVICE AND METHOD FOR FABRICATING THE SAME}

The present invention relates to an organic light emitting device (Organic Electroluminescent Device, hereinafter referred to as "OLED"), and more specifically, a flexible organic field capable of controlling the electrostatic phenomenon on a flexible substrate when manufacturing the organic light emitting device It relates to a light emitting device and a manufacturing method thereof.

An organic light emitting device, which is one of flat panel displays (FPDs), has high luminance and low operating voltage characteristics. In addition, because it is a self-emission type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, and has a response time of several microseconds (μs). It is also stable, and it is easy to manufacture and design a driving circuit because it is driven with a low voltage of 5 to 15 V DC.

The manufacturing process of the organic light emitting device is very simple because the deposition and encapsulation equipment can be said to be all.

Organic electroluminescent devices having these characteristics are largely classified into a passive matrix type and a matrix type. In the passive matrix method, a scan line and a signal line intersect to form a device in a matrix form, and each pixel In order to drive, since the scan lines are sequentially driven with time, in order to represent the required average luminance, the instantaneous luminance must be given as much as the average luminance multiplied by the number of lines.

However, in the active matrix method, a thin film transistor (TFT), which is a switching element that turns on/off a pixel area, is located for each pixel area, is connected to such a switching thin film transistor, and a driving thin film transistor is connected. It is connected to a power supply wiring and an organic light emitting diode, and is formed for each pixel area.

The first electrode connected to the driving thin film transistor is turned on/off in units of a pixel region, and the second electrode facing the first electrode serves as a common electrode, thereby interposing the two electrodes. In addition to the light emitting layer, the organic light emitting diode is formed.

In the active matrix method having this feature, the voltage applied to the pixel region is charged in the storage capacitor Cst, and the power is applied until the next frame signal is applied, so that the voltage is applied regardless of the number of scan lines. It continues to run during the screen.

Therefore, the active matrix type organic electroluminescent device has been used in recent years because it has the advantage of low power consumption, high definition, and large size because it exhibits the same luminance even when a low current is applied.

In addition, in recent years, a flexible display device to which such an organic light emitting device is applied and the possibility of practical use thereof have emerged as a major issue in the application of next-generation devices.

Most flexible display devices are manufactured by manufacturing a thin film transistor element and a device driven thereon through a number of processes on a flexible plastic substrate.

In this regard, the organic electroluminescent device according to the prior art will be described with reference to FIG. 1 as follows.

1 is a cross-sectional view schematically showing an organic light emitting device according to the prior art.

The organic light emitting device according to the prior art (not shown), as shown in Figure 1, is formed on the substrate 11 and a thin film transistor unit composed of a driving thin film transistor (not shown) and a switching thin film transistor (not shown) It comprises a (20) and an organic electroluminescent device 30 connected to the thin film transistor unit 20, and a protective film 40 encapsulating the organic electroluminescent device 30 (encapsulation).

A polyimide layer 13 is formed on the glass substrate 11, and a sacrificial layer (not shown) is formed between the polyimide layer 13 and the substrate 11.

On the polyimide layer 13, at least one buffer layer 15 made of an insulating material, for example, an inorganic insulating material, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is formed.

A method of attaching the flexible substrate to the back of the organic light emitting device according to the prior art made of the above configuration will be described with reference to FIGS. 2A and 2B.

2A and 2B are process cross-sectional views for schematically explaining a process of attaching a flexible substrate to a back surface of an organic light emitting device according to the prior art.

Referring to FIG. 2A, a polyimide layer 13, a buffer layer 15, a thin film transistor unit 20, an organic light emitting device 30, and a protective film encapsulating them on the substrate 11 An organic electroluminescent device 1 in which 40 are sequentially stacked is provided.

Next, referring to FIG. 2B, after cleaning the back surface of the substrate 11 of the organic light emitting device 10 to make the organic light emitting device 10 into a plastic organic light emitting device, the organic light emitting device The substrate 11 is detached from the organic electroluminescent device 1 by irradiating a laser on the back surface of (1). At this time, when the laser is irradiated, the sacrificial layer (not shown) interposed between the substrate 11 and the polyimide layer 13 is separated from the polyimide layer 13 by heat, so that the substrate 11 Is peeled from the organic electroluminescent device 1.

Subsequently, although not shown in the drawing, the flexible organic electroluminescence according to the prior art is laminated by laminating a flexible substrate (not shown) on the back surface of the polyimide layer 13 from which the substrate 11 is separated. The device 1 is manufactured.

However, according to the organic light emitting device according to the prior art, in order to manufacture a flexible organic light emitting device, at least one or more buffer layers formed of an inorganic insulating material and a flexible plastic insulating substrate are used. These buffer layers and the plastic insulating substrate are Very vulnerable to static electricity.

FIG. 3 is a photograph schematically showing a screen state in which electrostatic mura occurs when manufacturing an organic light emitting device according to the prior art.

Referring to FIG. 3, when laser irradiation is performed to peel the substrate 10 from the organic electroluminescent device 1 in order to manufacture a flexible organic electroluminescent device, static electricity is applied to the surface of the polyimide layer 13. You can see that Mura occurs a lot.

In addition, since the organic electroluminescent device according to the prior art deposits a plurality of buffer layers using an inorganic insulating material on the substrate, the substrate is removed from the organic electroluminescent device through laser irradiation, and thus it is impossible to remove static electricity.

The present invention is to solve the problems of the prior art, the object of the present invention is to further reduce the static electricity on the polyimide layer by interposing an inorganic film having a low surface resistance between the polyimide layer and the buffer insulating film when manufacturing a plastic organic light emitting device. It is to provide a flexible organic light emitting device that can be controlled and a method of manufacturing the same.

A flexible organic light emitting device according to the present invention for achieving the above object is a substrate having a display area including a plurality of pixel areas and a non-display area including a pad area outside thereof is defined; A polyimide layer formed on the substrate; A low resistance inorganic film formed on the polyimide layer; A buffer layer formed on the low-resistance inorganic film; A plurality of thin film transistors formed in each of the pixel regions on the buffer layer; An interlayer insulating film formed on the display area and the non-display area of the substrate including the thin film transistor; A passivation film formed on the interlayer insulating film; A planarization film formed on the passivation film; A first electrode formed in each pixel region on the planarization film and connected to a drain electrode of the thin film transistor; A pixel defining layer formed around and around each pixel region of the substrate including the first electrode; An organic emission layer separately formed for each pixel region on the first electrode; A second electrode formed on the front surface of the display region over the organic light emitting layer; A lower passivation film formed on the entire surface of the substrate including the second electrode; An organic layer formed on a lower passivation layer on the display area; An upper passivation film formed on the first passivation film including the organic film; And it characterized in that it comprises a protective film disposed on the upper passivation film.

In order to achieve the above object, a method of manufacturing a flexible organic light emitting device according to the present invention includes providing a substrate in which a display area including a plurality of pixel areas and a non-display area including a pad area outside thereof are defined; Forming a polyimide layer on the substrate; Forming a low-resistance inorganic film on the polyimide layer; Forming a buffer layer on the low-resistance inorganic film; Forming a plurality of thin film transistors in each pixel region on the buffer layer; Forming an interlayer insulating film on the entire surface of the substrate including the thin film transistor; Forming a passivation film on the interlayer insulating film; Forming a planarization film on the passivation film; Forming a first electrode connected to a drain electrode of the thin film transistor in each pixel region on the planarization layer; Forming a pixel defining layer around each pixel region of the substrate including the first electrode; Forming an organic light emitting layer for each pixel region on the first electrode; Forming a second electrode on the entire surface of the display area including the organic emission layer; Forming a lower passivation film on the entire surface of the substrate including the second electrode; Forming an organic layer on a lower passivation layer on the display area; Forming an upper passivation film on the first passivation film including the organic film; And forming a protective film on the upper passivation layer. And peeling the substrate from the polyimide layer. And it characterized in that it comprises a step of laminating a flexible (flexible) back plate on the surface of the polyimide layer.

According to the flexible organic light emitting device according to the present invention and a method for manufacturing the same, the buffer layer and the flexible substrate formed of an inorganic insulating material used to manufacture the flexible organic light emitting device are very vulnerable to static electricity. To this end, static electricity generated during the manufacturing process of the flexible substrate and the module can be controlled by interposing a low-resistance inorganic film that conducts electricity between the polyimide layer and the buffer layer.

In particular, the flexible organic light emitting device according to the present invention is a low-resistance inorganic film that is electrically conductive, and has a phosphorus (phosporus) or boron-doped microcrystalline silicon (μ-Crystalline Silicon) or a sheet resistance of 1 to 500 Ω/ □, deposition thickness is 500 to 1000 Å, dopant concentration is 1×10 ¹⁸ It is possible to effectively control static electricity generated during the manufacturing process of the flexible substrate and the module by using a material having an electrical conductivity of about 1×10 ¹⁹ .

Accordingly, the flexible organic light emitting device according to the present invention serves to effectively control the static electricity generated during the manufacturing process of the flexible substrate and the module due to the interposition of a low-resistance inorganic film that conducts electricity between the polyimide layer and the buffer layer. Therefore, it is possible to block the occurrence of multiple static electricity muras in the image quality due to the existing static electricity.

1 is a cross-sectional view schematically showing an organic light emitting device according to the prior art.
2A and 2B are process cross-sectional views for schematically explaining a process of attaching a flexible substrate to a back surface of an organic light emitting device according to the prior art.
FIG. 3 is a photograph schematically showing a screen state in which electrostatic mura occurs when manufacturing an organic light emitting device according to the prior art.
4 is a cross-sectional view schematically showing a flexible organic light emitting device according to the present invention.
5 is a cross-sectional view schematically showing a low resistance inorganic film and a plurality of buffer layers stacked on a polyimide layer when manufacturing the flexible organic light emitting device according to the present invention.
6A and 6B are process cross-sectional views for schematically explaining a process of attaching a flexible back plate to the back surface of the flexible organic light emitting device according to the present invention.
7A to 7U are cross-sectional views of a manufacturing process schematically showing a method of manufacturing a flexible organic light emitting device according to the present invention.
8 is a photograph schematically showing a screen state in which electrostatic mura is removed when manufacturing the flexible organic light emitting device according to the present invention.

Hereinafter, a flexible organic light emitting device according to a preferred embodiment of the present invention will be described in detail.

The configuration of the present invention and the effect of the effect will be clearly understood through the following detailed description. Prior to the detailed description of the present invention, the same components are indicated by the same reference numerals as possible even if they are displayed on different drawings, and the detailed description will be omitted when it is determined that the gist of the present invention may be obscured with respect to the known components. do.

The flexible organic light emitting device according to the present invention is divided into an upper emission type (top emission type) and a lower emission type (bottom emission type) according to the transmission direction of the emitted light. I'll do it.

A flexible organic light emitting device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a cross-sectional view schematically showing a flexible organic light emitting device according to the present invention.

Referring to FIG. 4, the flexible organic light emitting device 100 according to the present invention includes a thin film transistor T including a driving thin film transistor (not shown) and a switching thin film transistor (not shown), and an organic light emitting device E ) Is formed on the substrate 101 is encapsulated (encapsulation) by the protective film (151).

When the plastic organic light emitting device 100 is described in detail, as shown in FIG. 4, a display area (not shown) is defined on a glass substrate 101 and outside the display area (not shown). A non-display area (not shown) including a pad area is defined, and the display area includes a plurality of pixel areas (not shown) defined as areas captured by a gate line (not shown) and a data line (not shown). ) Is provided, and a power supply wiring (not shown) is provided in parallel with the data wiring (not shown).

Here, the substrate 101 of the glass material is peeled off after the organic light emitting device is manufactured, and a flexible back plate (not shown, see 161 of FIG. 7U) is laminated on the peeled portion. ), the back plate 161 is made of a flexible glass substrate or a plastic material having flexible characteristics to maintain display performance even when the flexible organic light emitting device (OLED) 100 is curved like paper.

In addition, an organic material polyimide layer (103) is formed on the substrate 101, and a low-resistance inorganic film 105 through which electricity is passed is formed on the polyimide layer 103. At this time, the low-resistance inorganic film 105 is formed of microcrystalline silicon (μ-Crystalline Silicon) doped with phosphorus (phosporus; PH ₃ ) or boron (B ₂ H ₆ ) in order to have the property of conducting electricity. Or other materials. In addition, the low-resistance inorganic film 105 has a sheet resistance of 1 to 500 Ω/□, a deposition thickness of 500 to 1000 Å, and a dopant concentration of 1×10 ^18. It may be used a material having an electrical conductivity of about 1 × 10 ¹⁹ degree.

In addition, a buffer layer 107 made of an inorganic insulating material is formed on the low-resistance inorganic film 105.

5 is a cross-sectional view schematically showing a low resistance inorganic film and a plurality of buffer layers stacked on a polyimide layer when manufacturing the flexible organic light emitting device according to the present invention.

Referring to FIG. 5, the buffer layer 107 includes at least one inorganic film, for example, a first inorganic film 107a, a second inorganic film 107b, a third inorganic film 107c, and a fourth inorganic film (107d). In this case, the first, 2, 3, and 4 inorganic films 107a, 107b, 107c, and 107d are selected from one or more of inorganic insulating materials including SiO ₂ , SiN, SiON, and SiH ₄ .

At this time, the reason for forming the buffer layer 107 under the active layer 109 formed in a subsequent process is that the active layer by the release of alkali ions from the inside of the substrate 101 at the time of crystallization of the active layer 109 ( This is to prevent deterioration of the properties of 109).

A sacrificial layer 102 made of amorphous silicon or silicon nitride (SiNx) is formed between the substrate 101 and the polyimide layer 103, and the sacrificial layer 102 is laser after manufacturing an organic light emitting device. (Laser) Through the irradiation process, the substrate 101 serves to facilitate peeling from the polyimide layer 103.

Further, each pixel area (not shown) in the display area AA above the buffer layer 107 is made of pure polysilicon, respectively, corresponding to a driving area (not shown) and a switching area (not shown), and the central part thereof An active layer 109 consisting of a channel region 109a forming a channel and a source region 109b and a drain region 109c doped with high concentrations of impurities are formed on both sides of the channel region 109a.

A gate insulating layer 113 is formed on the buffer layer 107 including the active layer 109, and each of the active layers (not shown) in the driving region (not shown) and the switching region (not shown) is formed on the gate insulating layer 113. A gate electrode 115a is formed corresponding to the channel region 109a of 109.

In addition, the gate insulating layer 113 is connected to the gate electrode 115a formed in the switching region (not shown) and extends in one direction to form a gate wiring (not shown). At this time, the gate electrode 115a and the gate wiring (not shown) are first metal materials having low resistance characteristics, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum ( Mo), and may have a single layer structure made of one of molybdenum (MoTi), or a double layer or a triple layer structure made of two or more of the first metal materials. In the drawing, as an example, the gate electrode 115a and the gate wiring (not shown) have a single layer structure.

On the other hand, an interlayer insulating film made of an insulating material, for example, an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), on the entire surface of the display area of the substrate including the gate electrode 115a and the gate wiring (not shown) 121) is formed. At this time, the source region 109b and the drain region 109c located on both sides of the channel region 109a of the active layer 109 are exposed to the interlayer insulating layer 121 and the gate insulating layer 113 under the layer, respectively. An active layer contact hole (not shown) is provided.

In addition, an upper portion of the interlayer insulating layer 121 including the active layer contact hole (not shown) crosses the gate wiring (not shown), defines the pixel area (not shown), and defines a second metal material, for example. Data wiring made of any one or more materials of aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum titanium (MoTi), chromium (Cr), titanium (Ti) (Not shown) and a power supply wiring (not shown) spaced apart from this. In this case, the power wiring (not shown) may be formed side by side apart from the gate wiring (not shown) on the layer on which the gate wiring (not shown) is formed, that is, the gate insulating layer 113.

Furthermore, the source region 109b and the drain region 109c spaced apart from each other in the driving region (not shown) and the switching region (not shown) on the interlayer insulating layer 121 are exposed through the active layer contact hole (not shown). ), and a source electrode 127a and a drain electrode 127b made of a second metal material identical to the data wiring (not shown) are formed. In this case, the active layer 109 and the gate insulating layer 113 and the gate electrode 115a and the interlayer insulating layer 121 sequentially stacked on the driving region (not shown) and the switching region (not shown) are formed to be spaced apart from each other. The source electrode 127a and the drain electrode 127b constitute a driving thin film transistor (not shown). In this case, in the present invention, the driving thin film transistor and the switching thin film transistor will be collectively described as the thin film transistor T.

On the other hand, in the drawings, although the data wiring (not shown) and the source electrode 127a and the drain electrode 127b both have a single layer structure, these components may form a double layer or triple layer structure. have.

At this time, although not shown in the drawing, a switching thin film transistor (not shown) having the same stack structure as the driving thin film transistor (not shown) is also formed in the switching region (not shown). In this case, the switching thin film transistor (not shown) is electrically connected to the driving thin film transistor (not shown), the gate wiring (not shown), and the data wiring (not shown). That is, the gate wiring (not shown) and the data wiring (not shown) are respectively connected to the gate electrode (not shown) and the source electrode (not shown) of the switching thin film transistor (not shown), and the switching thin film transistor ( The drain electrode (not shown) of the not shown) is electrically connected to the gate electrode 115a of the driving thin film transistor.

On the other hand, the driving thin film transistor (not shown) and the switching thin film transistor (not shown), that is, the thin film transistor T has an active layer 109 of polysilicon, and is shown as an example of a top gate type (Top gate type). , The thin film transistor T may also be of a bottom gate type having an active layer of amorphous silicon.

When the thin film transistor T is configured as a bottom gate type, the stacked structure is spaced apart from the active layer of a gate electrode/gate insulating film/pure amorphous silicon, and an active layer of an ohmic contact layer of impurity amorphous silicon/is spaced apart from each other. It is made of a source electrode and a drain electrode. At this time, the gate wiring is formed to be connected to the gate electrode of the thin film transistor on the layer on which the gate electrode is formed, and the data wiring is formed to be connected to the source electrode on the layer on which the source electrode of the switching thin film transistor is formed.

Meanwhile, a passivation film 131 and a planarization film 133 having a drain contact hole (not shown) exposing the drain electrode 127b of the thin film transistor T are stacked on the thin film transistor Tr. At this time, as the interlayer insulating layer 121, an insulating material, for example, an inorganic insulating material, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is used. In addition, the planarization layer 133 is selected and used from the group of organic materials including photo acryl.

A first electrode 137 that is in contact with the drain electrode 127b of the thin film transistor T and the drain contact hole (not shown) over the planarization layer 133 and has a separate shape for each pixel region. Is formed. At this time, the first electrode 137 may be provided as a transparent electrode and a reflective electrode. When used as a transparent electrode, it may be provided as ITO, IZO, ZnO, or In ₂ O ₃ , and may be used as a reflective electrode. At this time, after forming a reflective film with Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and these compounds, ITO, IZO, ZnO, or In ₂ O ₃ may be formed thereon. have.

In addition, a pixel defined by an insulating material, for example, benzocyclobutene (BCB), polyimide, or photo acryl, in the boundary region of each pixel region over the first electrode 137 A film 139 is formed. In this case, the pixel defining layer 139 is formed to overlap each pixel area (not shown) and overlaps the edge of the first electrode 137, and the display area AA has a plurality of openings as a whole. It has a lattice shape.

An organic emission layer 141 made of organic materials emitting red, green, and blue light is formed on the first electrode 137 in each pixel area surrounded by the pixel defining layer 139. The organic light emitting layer 141 may be composed of a single layer made of an organic light emitting material, or a hole injection layer, a hole transporting layer, and a light emitting layer (emitting) to increase light emission efficiency, although not shown in the drawings It may be composed of multiple layers of a material layer, an electron transporting layer, and an electron injection layer.

In addition, a second electrode 143 is formed on the entire surface of the display area AA including the organic emission layer 141 and the pixel defining layer 139. At this time, the first electrode 137 and the second electrode 143 and the organic light emitting layer 141 interposed between the two electrodes 137 and 141 constitute an organic electroluminescent device E.

Therefore, when a predetermined voltage is applied to the first electrode 137 and the second electrode 143 according to the selected color signal, the organic electroluminescent device E, holes and second injected from the first electrode 137 are applied. Electrons provided from the electrode 143 are transported to the organic emission layer 141 to form excitons, and when these excitons transition from an excited state to a ground state, light is generated and emitted in the form of visible light. At this time, since the emitted light passes through the transparent second electrode 143 and goes out, the plastic organic light emitting device embodies an arbitrary image.

On the other hand, a lower passivation film 145 made of an insulating material, particularly an inorganic insulating material, such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is formed on the entire surface of the substrate including the second electrode 143. At this time, since the penetration of moisture into the organic light emitting layer 141 cannot be completely suppressed by the second electrode 143 alone, the organic light emitting layer () is formed by forming the lower passivation film 145 over the second electrode 143. 141).

In addition, an organic layer 147 made of a polymer organic material such as a polymer is formed in the display area AA on the lower passivation layer 145. At this time, the polymer thin film constituting the organic film 147 is an olefin-based polymer (polyethylene, polypropylene), polyethylene terephthalate (PET), epoxy resin (epoxy resin), fluoro resin (fluoro resin), polysiloxane (polysiloxane), etc. Can be used.

In addition, an insulating material, for example, an inorganic insulating material, such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is formed on the front surface of the substrate including the organic layer 147 to prevent moisture from penetrating through the organic layer 147. ), an upper passivation film 149 is further formed.

A protective film 151 is positioned on the front surface of the substrate including the upper passivation film 149 for encapsulation of the organic light emitting device E. Between the substrate 101 and the protective film 151 An adhesive (not shown) made of any one of frit, organic insulating material, and polymer material having transparent and adhesive properties is completely interposed and interposed with the substrate 101 and the barrier film 151 without an air layer. The polarizing plate 153 is disposed on the protective film 151.

In this way, the substrate 101 and the barrier film 151 are fixed by an adhesive (not shown) to form a panel state, thereby forming the organic electroluminescent device 100 according to the present invention.

In this way, the flexible organic light emitting device according to the present invention is a buffer layer formed of an inorganic insulating material used for manufacturing a flexible organic light emitting device and the flexible substrate is very susceptible to static electricity, so polyimide to control such static electricity By interposing a low-resistance inorganic film through which electricity is passed between the layer and the buffer layer, static electricity generated during the manufacturing process of the flexible substrate and the module can be controlled.

In particular, the flexible organic light emitting device according to the present invention is a low-resistance inorganic film that is electrically conductive, and has a phosphorus (phosporus) or boron-doped microcrystalline silicon (μ-Crystalline Silicon) or a sheet resistance of 1 to 500 Ω/ □, deposition thickness is 500 to 1000 Å, dopant concentration is 1×10 ¹⁸ It is possible to effectively control static electricity generated during the manufacturing process of the flexible substrate and the module by using a material having an electrical conductivity of about 1×10 ¹⁹ .

Accordingly, the flexible organic light emitting device according to the present invention serves to effectively control the static electricity generated during the manufacturing process of the flexible substrate and the module due to the interposition of a low-resistance inorganic film that conducts electricity between the polyimide layer and the buffer layer. Therefore, it is possible to block the occurrence of multiple static electricity muras in the image quality due to the existing static electricity.

The method of peeling the substrate from the organic electroluminescent device according to the present invention having the above configuration will be schematically described with reference to FIGS. 6A and 6B.

6A and 6B are process cross-sectional views for schematically explaining a process of attaching a flexible back plate to the back surface of the flexible organic light emitting device according to the present invention.

Referring to FIG. 6A, in order to make the organic light emitting device 100 a flexible organic light emitting device, first, the back surface of the substrate 101 of the organic light emitting device 100 is cleaned, and then laser irradiation is performed. do.

Next, referring to FIG. 6B, through the laser irradiation, the sacrificial layer 102 interposed between the substrate 101 and the polyimide layer 105 is separated by heat, so that the substrate 101 is transferred to the organic electric field. Peel off from the light emitting device 100.

Subsequently, although not shown in the drawings, the lamination of the flexible organic electroluminescent device according to the present invention is performed by laminating a back plate (not shown) on the surface of the polyimide layer 105 of the separated organic electroluminescent device. The manufacturing process is completed.

Meanwhile, a method of manufacturing an organic light emitting device according to the present invention will be described with reference to FIGS. 7A to 7U.

7A to 7U are cross-sectional views of a manufacturing process schematically showing a method of manufacturing a flexible organic light emitting device according to the present invention.

As shown in FIG. 7A, a substrate 101 made of a glass material having a display area AA and a non-display area (not shown) including a pad area PD outside the display area AA is prepared. do. At this time, the substrate 101 is peeled after the organic electroluminescent device is manufactured, and a flexible back plate (not shown, 161 of FIG. 7s) is laminated to the peeled portion, and the back plate ( 161) is made of a plastic (flexible) glass substrate or a plastic material having a flexible property to maintain the display performance even if the plastic organic light emitting device (OLED) is curved like paper.

Then, an organic material, a polyimide layer (105) and an electrically conductive low-resistance inorganic film 105 are sequentially stacked on the substrate 101. At this time, the low-resistance inorganic film 105 is formed of microcrystalline silicon (μ-Crystalline Silicon) doped with phosphorus (phosporus; PH ₃ ) or boron (B ₂ H ₆ ) in order to have the property of conducting electricity. Or other materials. In addition, the low-resistance inorganic film 105 has a sheet resistance of 1 to 500 Ω/□, a deposition thickness of 500 to 1000 Å, and a dopant concentration of 1×10 ^18. It may be used a material having an electrical conductivity of about 1 × 10 ¹⁹ degree.

In addition, a sacrificial layer 102 made of amorphous silicon or silicon nitride (SiNx) is formed between the substrate 101 and the polyimide layer 103, after which the sacrificial layer 102 is manufactured. In the laser (Laser) through the irradiation process, the substrate 101 plays a role of easily peeling off the polyimide layer 103.

Subsequently, as shown in FIG. 7B, a buffer layer 107 made of an inorganic insulating material is formed on the low-resistance inorganic film 105. In this case, referring to FIG. 5, the buffer layer 107 may include at least one inorganic film, for example, a first inorganic film 107a, a second inorganic film 107b, a third inorganic film 107c, and 4 It consists of the laminated structure of the inorganic film 107d. In this case, the first, 2, 3, and 4 inorganic films 107a, 107b, 107c, and 107d are selected from one or more of inorganic insulating materials including SiO ₂ , SiN, SiON, and SiH ₄ .

The buffer layer 107 plays a role of preventing the deterioration of the properties of the active layer 109 due to the release of alkali ions from the inside of the substrate 101 during crystallization of the active layer 109 formed in a subsequent process.

Next, as shown in FIG. 7C, an active layer 109 is formed on the buffer layer 107. In this case, the active layer 109 is made of pure polysilicon, respectively, corresponding to a driving region (not shown) and a switching region (not shown) for each pixel region in the display area (not shown).

Subsequently, a first photoresist layer (not shown) is coated on the active layer 109, and the first photoresist layer (not shown) is selectively patterned through an exposure process and a development process to form a first photoresist layer pattern 111. .

Next, as shown in FIG. 7D, the active layer 109 is selectively removed by using the first photoresist layer pattern 111 as an etch mask to form the active layer pattern 109a.

Subsequently, as illustrated in FIG. 7E, after removing the first photoresist layer pattern 111, a gate insulating layer 113 and a first metal material layer 115 on the buffer layer 107 including the active layer pattern 109a ) In turn. In this case, the first metal material layer 115 is a first metal material having low resistance properties, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum It may be formed of any one of titanium (MoTi) to have a single layer structure, or may be formed of two or more of the first metal materials to have a double layer or triple layer structure. In the drawing, as an example, the gate electrode and the gate wiring (not shown) have a single layer structure.

Then, after applying a second photoresist layer (not shown) on the first metal material layer 115, the second photoresist pattern (not shown) is selectively patterned through an exposure and development process to form a second photoresist pattern ( 117).

Subsequently, as illustrated in FIG. 7F, the first metal material layer 115 is selectively etched using the second photoresist layer pattern 117 as an etch mask to form a gate electrode 115a. At this time, a gate wiring (not shown) is formed on the gate insulating layer 113 and connected to the gate electrode 115a formed in the switching region (not shown) and extending in one direction.

Next, as illustrated in FIG. 7G, the second photoresist layer pattern 117 is removed, impurities are injected into the active layer pattern 109a under both sides of the gate electrode 115a, and the active layer pattern 109a is injected. A channel region 109a constituting a channel is formed in the center, and a source region 109b and a drain region 109c spaced apart from the channel region 109a are formed.

Subsequently, after removing the second photoresist pattern 117, an insulating material, for example, an inorganic insulating material, such as silicon oxide (SiO ₂ ) or nitride, over the gate electrode 115a and the gate wiring (not shown). An interlayer insulating film 121 made of silicon (SiNx) is formed.

Next, a third photoresist layer (not shown) is applied on the interlayer insulating layer 121, and then selectively patterned through an exposure and development process to form a third photoresist layer pattern 123.

Subsequently, as illustrated in FIG. 7H, the source of the active layer pattern 109a by selectively etching the interlayer insulating layer 121 and the gate insulating layer 113 under the third photoresist layer pattern 123 as an etching mask The source region contact hole 125a and the drain region contact hole 125b exposing the region 109b and the drain region 109c are simultaneously formed.

Next, as illustrated in FIG. 7I, the third photoresist layer pattern 123 is removed, and the source region 109b and drain region 109c of the active layer pattern 109a are formed on the interlayer insulating layer 121. A second metal material layer 127 in contact is formed. At this time, the second metal material layer 127 is aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum titanium (MoTi), chromium (Cr), titanium (Ti) ).

Subsequently, a third photoresist layer (not shown) is coated on the second metal material layer 127, and is patterned through an exposure and development process to form a third photoresist pattern 129.

Next, as illustrated in FIG. 7J, the second metal material layer 127 is selectively etched using the third photoresist layer pattern 129 as an etch mask to cross the gate wiring (not shown), and the A data wiring (not shown) defining a pixel area (not shown) and a power wiring (not shown) spaced apart therefrom are formed. In this case, the power wiring (not shown) may be formed in parallel with the gate wiring (not shown) spaced apart from the gate wiring (not shown) on the layer on which the gate wiring (not shown) is formed.

In addition, when forming the data wiring (not shown), spaced apart from each other in the driving region (not shown) and the switching region (not shown) over the interlayer insulating layer 121, the source region contact hole 125a and the drain region The source electrode 127a made of a second metal material that is in contact with the source region 109b and the drain region 109c of the active layer pattern 109a through the contact hole 125b, and is the same as the data wiring (not shown), and The drain electrode 127b is formed at the same time. In this case, the source electrode 127a and the drain formed spaced apart from the active layer 109, the gate insulating layer 113, the gate electrode 115a, and the interlayer insulating layer 121 sequentially stacked in the driving region (not shown) The electrode 127b constitutes a thin film transistor T.

On the other hand, in the drawing, although the data wiring (not shown) and the source electrode 127a and the drain electrode 127b both show a single layer structure as an example, these components may form a double layer or triple layer structure. have.

In this case, although not shown in the drawing, the driving thin film transistor, that is, a switching thin film transistor (not shown) having the same stacked structure as the thin film transistor T is also formed in the switching region (not shown). The switching thin film transistor (not shown) is electrically connected to the driving thin film transistor (not shown), the gate wiring (not shown), and the data wiring (not shown). That is, the gate wiring (not shown) and the data wiring (not shown) are respectively connected to the gate electrode (not shown) and the source electrode (not shown) of the switching thin film transistor (not shown), and the switching thin film transistor ( The drain electrode (not shown) of the not shown) is electrically connected to the gate electrode 115a of the thin film transistor T.

On the other hand, the organic light emitting device according to the present invention, the thin film transistor T including the driving thin film transistor (not shown) and the switching thin film transistor (not shown) has an active layer pattern 109a of polysilicon, and is a top gate type (Top gate type) is shown as an example, but the driving switching thin film transistor and the switching thin film transistor (not shown) may be configured as a bottom gate type (Bottom gate type) having an active layer of amorphous silicon.

When the driving thin film transistor, that is, the thin film transistor T is configured as a bottom gate type, the stacked structure is spaced apart from the active layer of the gate electrode/gate insulating film/pure amorphous silicon, and an active layer made of an ohmic contact layer of impurity amorphous silicon And a source electrode and a drain electrode spaced apart from each other. At this time, the gate wiring is formed to be connected to the gate electrode of the thin film transistor on the layer on which the gate electrode is formed, and the data wiring is formed to be connected to the source electrode on the layer on which the source electrode of the switching thin film transistor is formed.

Subsequently, as illustrated in FIG. 7K, after removing the third photosensitive film pattern 129, a passivation film 131 is formed on the entire surface of the substrate including the source electrode 127a and the drain electrode 127b. At this time, an insulating material, for example, an inorganic insulating material, such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is used as the passivation film 131.

Next, as shown in FIG. 7L, a planarization film 133 made of an organic material is formed on the passivation film 131. At this time, as the organic material, as a hydrophobic organic system having insulating properties, it can be selected and used from the group consisting of polyacryl, polyimide, polyamide (PA), benzocyclobutene (BCB) and phenol resin. have.

Subsequently, as shown in FIG. 7M, the planarization layer 133 and the passivation layer 131 underneath are sequentially etched to form a drain contact hole 135 exposing the drain electrode 127b.

Next, as shown in FIG. 7N, after depositing a conductive material layer (not shown) on the planarization layer 133, the conductive contact layer 135 is selectively etched through a mask process to selectively etch the conductive contact layer 135 ) To form a first electrode 137 that is in contact with the drain electrode 127b of the thin film transistor T and has a separate shape for each pixel region. At this time, the conductive material layer (not shown) may be provided as a transparent electrode and a reflective electrode. When used as a transparent electrode, ITO, IZO, ZnO, or In ₂ O ₃ may be provided as a reflective electrode. When used, a reflective film is formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and a compound thereof, and then ITO, IZO, ZnO, or In ₂ O ₃ is formed thereon. It might be.

Subsequently, as illustrated in FIG. 7O, for example, benzocyclobutene (BCB), polyimide, or photo acryl is formed on the first electrode 137 at the boundary region of each pixel region. An insulating material layer (not shown) is formed.

Then, the insulating material layer (not shown) is selectively patterned through a mask process to form a pixel defining layer 139. In this case, the pixel defining layer 139 is formed to surround each pixel area so as to overlap the border of the first electrode 137, and forms a lattice form having a plurality of openings throughout the display area AA. have.

Subsequently, as illustrated in FIG. 7P, an organic emission layer 141 emitting red, green, and blue light is formed on the first electrode 137 in each pixel region surrounded by the pixel defining layer 139. At this time, the organic light-emitting layer 141 may be composed of a single layer made of an organic light-emitting material, or, although not shown in the drawing, a hole injection layer (hole injection layer), hole transport layer (hole transporting layer), light emission to increase the luminous efficiency It may be composed of multiple layers of a material layer, an electron transporting layer, and an electron injection layer.

Next, as illustrated in FIG. 7Q, a second electrode 143 is formed on the entire surface of the display area (not shown) including the organic emission layer 141 and the pixel defining layer 139. At this time, the second electrode 143 may be provided as a transparent electrode or a reflective electrode. When used as a transparent electrode, since the second electrode 143 is used as a cathode electrode, a metal having a small work function, that is, Li, Ca , LiF/Ca, LiF/Al, Al, Ag, Mg, and their compounds are deposited to face the direction of the organic layer 129, and thereafter, transparent electrodes such as ITO, IZO, ZnO, or In ₂ O ₃ An auxiliary electrode layer or a bus electrode line may be formed of a forming material. In addition, when used as a reflective electrode, Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, and their compounds are formed by vapor deposition.

Therefore, the organic electroluminescent element E is connected to the drain electrode 127b of the thin film transistor, and is provided with a first electrode 137 supplying positive power therefrom, and a second electrode provided to cover all pixels to supply negative power. It is composed of an electrode 143 and an organic light emitting layer 141 disposed between the first electrode 137 and the second electrode 143 to emit light, and emits red, green, and blue light according to current flow. Displays predetermined image information.

The first electrode 137 and the second electrode 143 are insulated from each other by the organic light emitting layer 141, and light is emitted from the organic light emitting layer 141 by applying voltages of different polarities to the organic light emitting layer 141. Will be done.

When the predetermined voltages are applied to the first electrode 137 and the second electrode 143 according to the selected color signal, the organic light emitting diode E may have holes and second electrodes injected from the first electrode 137 ( Electrons provided from 141) are transported to the organic light emitting layer 141 to form excitons, and when these excitons transition from an excited state to a ground state, light is generated and emitted in the form of visible light. At this time, since the emitted light passes through the transparent second electrode 143 and goes out, the plastic organic light emitting device embodies an arbitrary image.

Subsequently, as illustrated in FIG. 7R, a lower passivation film 145 made of an insulating material, particularly an inorganic insulating material, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is formed on the entire surface of the substrate including the second electrode 143. To form. At this time, since the penetration of moisture into the organic light emitting layer 141 cannot be completely suppressed by the second electrode 143 alone, the organic light emitting layer () is formed by forming the lower passivation layer 145 over the second electrode 143. 141).

Next, an organic film 147 made of a polymer organic material such as a polymer is formed on a display area and a non-display area on the lower passivation film 145 through a coating method such as a screen printing method. . At this time, the polymer thin film constituting the organic film 147 is an olefin-based polymer (polyethylene, polypropylene), polyethylene terephthalate (PET), epoxy resin (epoxy resin), fluoro resin (fluoro resin), polysiloxane (polysiloxane), etc. Can be used. The organic layer 147 is formed on the display area (not shown).

Subsequently, an insulating material, for example, an inorganic insulating material, such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), is used to prevent moisture from penetrating through the organic film 147 on the entire surface of the substrate including the organic film 147. ), an upper passivation film 149 is further formed.

Next, a protective film 151 is formed on the entire surface of the substrate including the upper passivation film 149 for encapsulation of the organic light emitting device E. Between the substrate 101 and the protective film 151 After the transparent and adhesive properties of the frit (frit), an organic insulating material, a pressure-sensitive adhesive (not shown) made of any one of the polymer material, without the air layer, the substrate 101 and the protective film 151 is completely in contact with , A polarizing plate 153 is attached to the protective film 151.

In this way, the substrate 101 and the barrier film 151 are fixed by an adhesive (not shown) to form a panel state, thereby completing the organic electroluminescent device manufacturing process according to the present invention.

Subsequently, as shown in FIG. 7s, in order to make the organic electroluminescent device 100 having the above configuration into a flexible organic electroluminescent device, the back surface of the substrate 101 of the organic electroluminescent device is cleaned, and then the substrate (101) is irradiated with a laser.

Subsequently, as shown in FIG. 7T, the substrate 101 is removed by thermally separating the sacrificial layer 103 interposed between the substrate 101 and the polyimide layer 105 through the laser irradiation. Peel off from the electroluminescent device 100.

Then, as shown in Figure 7u, the flexible organic electroluminescence according to the present invention by lamination (Back Plate) 161 on the surface of the polyimide layer 103 of the separated organic electroluminescent device (Lamination) The manufacturing process of the device 100 is completed.

8 is a photograph schematically showing a screen state in which electrostatic mura is removed when manufacturing the flexible organic light emitting device according to the present invention.

Referring to FIG. 8, between the polyimide layer 105 formed on the substrate 101 and the inorganic film 107, a low-resistance inorganic film 105 that conducts electricity is formed on the polyimide layer 103. It can be seen that the image quality is improved by controlling the static electricity.

As described above, the method of manufacturing a flexible organic electroluminescent device according to the present invention, since the buffer layer and the flexible substrate formed of an inorganic insulating material used to manufacture the flexible organic electroluminescent device are very susceptible to static electricity, this static electricity To control, static electricity generated during the manufacturing process of the flexible substrate and the module can be controlled by interposing a low-resistance inorganic film through which electricity is passed between the polyimide layer and the buffer layer.

Particularly, the flexible organic light emitting device according to the present invention is a low-resistance inorganic film that is electrically conductive, and has a phosphorus or boron-doped micro-crystalline silicon or a surface resistance of 1 to 500 Ω/ □, deposition thickness is 500 to 1000 Å, dopant concentration is 1×10 ¹⁸ It is possible to effectively control static electricity generated during the manufacturing process of the flexible substrate and the module by using a material having an electrical conductivity of about 1×10 ¹⁹ .

Accordingly, the flexible organic light emitting device according to the present invention serves to effectively control the static electricity generated during the manufacturing process of the flexible substrate and the module due to the interposition of a low-resistance inorganic film that conducts electricity between the polyimide layer and the buffer layer. Therefore, it is possible to block the occurrence of multiple static electricity muras in the image quality due to the existing static electricity.

Those skilled in the art to which the present invention pertains will appreciate that the above-described present invention can be implemented in other specific forms without changing its technical spirit or essential features.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modifications derived from the meaning and scope of the claims and equivalent concepts are included in the scope of the present invention. do.

100: organic light emitting device 101: substrate
102: sacrificial layer 103: polyimide layer
105: low resistance inorganic film 107: buffer layer
109a: active layer pattern 113: gate insulating film
115a: gate electrode 121: interlayer insulating film
123: third photoresist pattern 127a: source electrode
127b: drain electrode 131: passivation film
133: planarization film 135: drain contact hole
137: first electrode 139: pixel defining layer
141: organic light emitting layer 143: second electrode
145: lower passivation film 147: organic film
149: upper passivation film 151: protective film
153: polarizing plate 161: back plate (Back Plate)

Claims (11)

A substrate in which a display area including a plurality of pixel areas and a non-display area including a pad area outside thereof are defined;
A polyimide layer formed on the substrate;
A low resistance inorganic film formed on the polyimide layer and conducting electricity;
A buffer layer formed on the low-resistance inorganic film;
A plurality of thin film transistors formed in each of the pixel regions on the buffer layer;
An interlayer insulating film and a planarization film stacked on the display area and the non-display area of the substrate including the thin film transistor;
An organic light emitting element formed in each pixel region on the planarization layer and electrically connected to the thin film transistor; And
And a protective film covering the organic light emitting device.
The buffer layer is composed of at least one inorganic film made of a silicon-based inorganic material, and the low-resistance inorganic film is made of a silicon-based inorganic material, and the silicon-based inorganic material of the buffer layer and the silicon-based inorganic material of the low-resistance inorganic film form an interface,
The thin film transistor includes an active layer pattern formed on the buffer layer, a gate electrode overlapping the active layer pattern with a gate insulating film interposed therebetween, and a source electrode and a drain electrode connected to the active layer,
The lower surface of the low-resistance inorganic film directly contacts the upper surface of the polyimide layer,
The upper surface of the low-resistance inorganic film directly contacts the lower surface of the buffer layer,
The active layer pattern is a flexible organic light emitting device in direct contact with the upper surface of the buffer layer. The flexible organic electroluminescence according to claim 1, wherein the low-resistance inorganic film is formed of phosporus (PH ₃ ) or boron (B ₂ H ₆ ) doped microcrystalline silicon (μ-Crystalline Silicon). Device. The method of claim 1, wherein the low-resistance inorganic film has a sheet resistance of 1 to 500 Ω/□, a deposition thickness of 500 to 1000 mm 2, and a dopant concentration of 1×10 ^18. The flexible organic light emitting device, characterized in that formed of a material having an electrical conductivity of about 1 × 10 ¹⁹ . delete The flexible organic electroluminescent device according to claim 1, wherein the inorganic film is selected from one or more of inorganic insulating materials including SiO ₂ , SiN, SiON, and SiH ₄ . Providing a substrate on which a display area including a plurality of pixel areas and a non-display area including a pad area are defined;
Forming a polyimide layer on the substrate;
Forming a low-resistance inorganic film on the polyimide layer;
Forming a buffer layer on the low-resistance inorganic film;
Forming a plurality of thin film transistors in each pixel region on the buffer layer;
Forming an organic electroluminescent element electrically connected to the thin film transistor on the entire surface of the substrate including the thin film transistor;
Forming a protective film covering the organic electroluminescent element;
Separating the substrate from the polyimide layer by irradiating a laser on the rear surface of the substrate; And
And laminating a flexible back plate on the surface of the polyimide layer.
The buffer layer is composed of at least one inorganic film made of a silicon-based inorganic material, and the low-resistance inorganic film is made of a silicon-based inorganic material. Method for manufacturing electroluminescent device. The flexible organic electroluminescence according to claim 6, wherein the low-resistance inorganic film is formed of phosporus (PH ₃ ) or microcrystalline silicon doped with boron (B ₂ H ₆ ). Device manufacturing method. The method of claim 6, wherein the low-resistance inorganic film has a sheet resistance of 1 to 500 Ω/□, a deposition thickness of 500 to 1000 Å, and a dopant concentration of 1×10 ^18. To 1 × 10 ¹⁹ flexible organic electroluminescent device manufacturing method characterized in that it is formed of a material having an electrical conductivity. delete The method of claim 6, wherein the inorganic film is selected from one or more of inorganic insulating materials including SiO ₂ , SiN, SiON, and SiH ₄ and used. The thin film transistor of claim 6, wherein the thin film transistor includes an active layer pattern formed on the buffer layer, a gate electrode overlapping the active layer pattern with a gate insulating film interposed therebetween, and a source electrode and a drain electrode connected to the active layer,
The lower surface of the low-resistance inorganic film directly contacts the upper surface of the polyimide layer,
The active layer pattern is a method of manufacturing a flexible organic electroluminescent device, characterized in that in direct contact with the upper surface of the buffer layer.

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