CN107644949B - Methods of Forming Inorganic Thin Layers on OLEDs - Google Patents

Abstract

The present invention relates to a method for forming an inorganic thin layer on an OLED, especially a method for forming an aluminum oxide thin film on an organic light emitting diode substrate by an atomic layer deposition method. The method comprises the following steps: 1) Mounting on a discharge line A moisture removal trap, the exhaust line is used to exhaust gas in a vacuum chamber provided with a process gas supply unit and a process gas exhaust unit; 2) Prepare organic light emitting diodes to be formed thereon 3) carrying the substrate into the interior of the vacuum chamber; 4) removing the vacuum chamber by opening a gate valve installed in front of the moisture removal trap 5) forming an aluminum oxide film on the substrate by atomic deposition using _H2O as the process gas; and 6) by opening a gate valve installed in front of the moisture removal trap to remove moisture from the vacuum chamber in which the thin film deposition process is completed.

Description

Methods of Forming Inorganic Thin Layers on OLEDs

technical field

The present invention relates to a method of forming an aluminum oxide thin film on an organic light emitting diode substrate, and more particularly to a method of forming an aluminum oxide thin film on an organic light emitting diode substrate by an atomic layer deposition method, which can be achieved by A perfect moisture removal process to prevent damage to organic light emitting diodes, while at the same time efficiently forming aluminum oxide films on organic light emitting diode substrates by atomic layer deposition method using water.

Background technique

Recently, image display devices that implement various kinds of information into screens are moving toward implementing the devices to have high performance while being thinner, lighter, and easy to carry, thanks to core technologies in the information communication age. The demand for image display devices has led to various flat panel display devices such as Liquid Crystal Displays (LCD), Plasma Display Panels (PDP), Electroluminescent Displays (ELDs), Field Emission Displays (FEDs), Organic Light Emitting Displays (OLEDs), etc. technology research and development.

In particular, research and development has recently focused on OLEDs capable of implementing flexible features of image display devices. An OLED is a display device that displays an image by controlling the amount of light emitted from an organic light-emitting layer for injecting electrons and holes from an electron injection electrode (cathode) and a hole injection electrode (anode) A device that emits light in a light-emitting layer and when excitons that combine injected electrons and holes fall from an excited state to a ground state.

An active matrix OLED (AMOLED) among OLEDs displays an image by arranging pixels composed of 3-color (R, G, B) sub-pixels controlled by active elements in a matrix. Therefore, each sub-pixel is provided with an organic electroluminescence device and a single driving unit for driving the organic electroluminescence device. The single driving unit includes at least two thin film transistors and includes a storage capacitor to control the brightness of the organic light emitting display device by controlling an amount of current supplied to the organic electroluminescent device according to a data signal.

OLEDs are fabricated in a method of forming an element substrate by forming a plurality of cells on a parent substrate that define active and passive regions, forming frits around the active regions, and cutting the parent substrate along scribe lines Bottom to configure the unit panel.

At this point, inner leads such as gate lines and data lines formed in the active area are connected to on/off pads and flexible printed circuit (FPC) pads, and then lead through pads extending toward the outside Connect to shorting bars, etc. The on/off pads are used to confirm that the lead network inside the device is working properly and that the FPC pads are connected to the driver circuit substrate through the FPC.

Although OLEDs with this structure have several advantages, there are still problems to be solved, that is, it is difficult to develop a technology for mass production of large-scale OLEDs, and if moisture and oxygen in the air are not effectively blocked, the The lifetime is drastically reduced due to the occurrence of defects such as dark spots.

In particular, if an organic light-emitting structure including an organic electroluminescent device and a monomer driving unit is formed on a polymer substrate such as polyimide to implement flexible display, the transmission speed of moisture and oxygen of the polymer substrate will be much higher than glass substrates, and thus encapsulation methods for organic light emitting structures have recently received increasing attention.

In the case of AMOLEDs, it is known that the value of the water vapor transmission rate (WVTR), which is an evaluation scale for the moisture vapor transmission rate, should be 10 ⁻⁶ g/m ² or less per day. To this end, instead of the encapsulation method using a glass substrate, a method of stacking multiple layers of films (as shown in FIG. 1 ) for preventing moisture and oxygen from permeating into the substrate on which the element is formed has recently become a The encapsulation method is proposed.

On the other hand, as shown in FIG. 1 , a thin film encapsulation method for having excellent blocking moisture by sequentially stacking on the substrate 10 on which the organic light emitting diodes 30 are formed has also been proposed The inorganic thin film 40 and the organic thin film 50 of gas and oxygen properties are used to encapsulate the light emitting diode 30 . In this regard, barrier layer 20 is typically formed on substrate 10 .

However, since a technology for mass-producing a large-scale OLED related to the encapsulation method has not been developed so far, in particular, there is an urgent need to develop a technology for forming an inorganic thin film.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above-mentioned problems occurring in the related art, and an object of the present invention is to provide a method capable of efficiently using an atomic layer deposition method using water on an organic light emitting diode substrate A thin film of aluminum oxide is formed and the damage of the organic light emitting diode can be prevented by the process of perfectly removing the moisture absorbed in the reaction chamber.

In order to achieve the above object, according to one aspect of the present invention, a method for forming an aluminum oxide film is provided, wherein the method for forming an aluminum oxide film forms an aluminum oxide film on an organic light emitting diode substrate by an atomic layer deposition method, and the The method includes the following steps: 1) installing a moisture removal trap on an exhaust line for exhausting gas in a vacuum chamber provided with a process gas supply unit and a process gas exhaust unit 2) prepare the substrate on which the organic light emitting diodes are formed; 3) carry the substrate to the interior of the vacuum chamber; 4) by opening the front gate of the moisture removal trap valve to remove moisture in the vacuum chamber; 5) forming an aluminum oxide film on the substrate with an atomic deposition method using _H2O as a process gas; and 6) by opening the moisture transfer A gate valve installed in front of the trap removes moisture from the vacuum chamber in which the thin film deposition process is completed.

Furthermore, in the present invention, it is preferable that the moisture removal trap is installed in front of the turbo pump of the discharge line.

Further, in the present invention, it is preferable to perform step 5) using the process gas discharge unit when the gate valve is closed, and to perform step 5) by opening the gate valve when performing steps other than step 5). Maintain a moisture-free state.

Description of drawings

FIG. 1 is a diagram showing the structure of a general organic light emitting diode substrate.

FIG. 2 is a diagram showing the structure of an atomic layer deposition apparatus according to an embodiment of the present invention.

3 is a flowchart illustrating a method of forming an aluminum oxide thin film on an organic light emitting diode substrate by an atomic layer deposition method according to an embodiment of the present invention.

Description of reference numerals

100: Atomic layer deposition apparatus according to an embodiment of the present invention

110: Vacuum Chamber

120: Process gas supply unit

130: Process gas discharge unit

140: Drain line

150: Moisture Removal Trap

Detailed ways

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

The method of forming an aluminum oxide thin film on an organic light emitting diode substrate by an atomic layer deposition method according to this embodiment starts from the step of preparing the organic light emitting diode substrate (step S100 ) as shown in FIG. 3 . The organic light emitting diode substrate is a structure in which a plurality of organic light emitting diodes are formed in a matrix form on a glass substrate or the like, and in which an encapsulation film for protecting the organic light emitting diodes is not formed.

As shown in FIG. 2 , the process gas supply unit 120 , the process gas discharge unit 130 , the discharge line 140 and the moisture removal trap 150 are installed in the vacuum chamber 110 in which the atomic layer deposition method is performed 110.

The process gas supply unit 120 is a component installed on one side of the vacuum chamber 110 (as shown in FIG. 2 ) to supply process gas or the like to the inside of the vacuum chamber 110 . Further, the process gas discharge unit 130 is a component for discharging the process gas or the like used in the process to the outside. Therefore, the process of depositing the atomic layer on the organic light emitting diode substrate is performed while the process gas supply unit 120 and the process gas discharge unit 130 supply and discharge various gases in pulses and the operation of the discharge line is excluded.

In addition, the exhaust line 140 is used in the exhaust process to generate and maintain a predetermined degree of vacuum level inside the vacuum chamber 110 . Thus, the discharge line 140 is generally composed of a turbo pump 144 , a drying pump 146 connected to the turbo pump 144 , and a gate valve 148 for opening and closing a conduit 142 connected to the turbo pump 144 .

Furthermore, in this embodiment, the moisture removal trap 150 is preferably installed in front of the turbo pump 144 of the discharge line 140 as shown in FIG. 2 . Therefore, when the gate valve 148 is opened by the moisture removal trap 150, all moisture in the vacuum chamber 110 can be absorbed and removed. Various structures may be used for the moisture removal trap 150, and for example, structures that trap exhaust gas using vapor pressure differences or solubility differences at extremely low temperatures obtained by using gases such as helium may be used moisture in.

Next, a step of carrying the substrate into the vacuum chamber 110 is performed (step S200). In this step, when a gate valve (not shown in the figure) installed on the side wall or the like of the vacuum chamber to carry the substrate to the inside of the vacuum chamber is opened, the organic light emitting device prepared in the previous step is opened. The diode substrate is carried into the vacuum chamber and placed at a process (processing) location inside the vacuum chamber.

Next, a step of opening the gate valve 148 in front of the moisture removing trap 150 and removing moisture in the vacuum chamber 110 is performed (step S300). This step is performed together with the process of previously venting the gas inside the vacuum chamber before performing the process, and preferably, this step is performed before carrying the organic light emitting diode substrate into the vacuum chamber.

Furthermore, because this step is performed in a simple method using only the operation of opening the gate valve 148 of the drain line 140, it can be performed at the same time and in the same method as the conventional drain process.

Next, a step of forming an aluminum oxide thin film on the organic light emitting diode substrate by an atomic deposition method using H ₂ O as a process gas is performed (step S400 ). Since an ordinary method of forming an Al ₂ O ₃ thin film on a substrate by an atomic deposition method can be used in this step, a detailed description of this step will be omitted.

Obviously, this step is performed using the process gas supply unit 120 and the process gas discharge unit 130 when the gate valve 148 is closed (step S400).

Next, a step of opening the gate valve 148 in front of the moisture removing trap 150 and removing moisture inside the vacuum chamber 110 in which the thin film deposition process has been completed is performed (step S500 ). This step is performed immediately after the process is completed to prevent damage to the organic light emitting diode by immediately removing moisture inside the vacuum chamber 110 in which the process is completed. Obviously, the specific method of removing the moisture is carried out in the same manner as the steps of removing the moisture in advance.

Preferably, the gate valve 148 is open at all times except for the step of forming the aluminum oxide film.

Next, the substrate may be disassembled to the outside (step S600), or additional processes may be performed.

According to the present invention, an aluminum oxide thin film can be efficiently formed on an organic light emitting diode susceptible to moisture erosion according to an atomic deposition method using vapor, and the organic light emitting diode in the deposition process can be completely removed by removing before and after the process Moisture comes not damaged by moisture.

Although the present invention has been described with reference to certain illustrative embodiments, the invention is not limited to the described embodiments but only by the appended claims. It should be appreciated that those skilled in the art can change or modify the described embodiments without departing from the scope and spirit of the present invention.

Claims (2)

1. A method for forming an aluminum oxide film, the method for forming an aluminum oxide film using an atomic layer deposition method to form an aluminum oxide film on an organic light-emitting diode substrate, and the method for forming an aluminum oxide film comprises the following steps: 1) A moisture removal trap is installed on the discharge line, and the discharge line is used to discharge the gas in the vacuum chamber, and the vacuum chamber is provided with a process gas supply unit and a process gas discharge unit; 2) preparing the substrate on which the organic light emitting diode is formed; 3) carrying the substrate into the interior of the vacuum chamber; 4) opening the gate valve in front of the moisture removal trap to remove moisture from the vacuum chamber; 5) closing the gate valve and opening the process gas supply unit and the process gas discharge unit to form an aluminum oxide film on the substrate by an atomic deposition method using H ₂ O as a process gas; and 6) opening the gate valve and closing the process gas supply unit and the process gas discharge unit in order to remove moisture in the vacuum chamber in which the thin film deposition process is completed, Wherein, when the gate valve is closed, step 5) is performed using the process gas discharge unit, and when steps other than step 5) are performed, a moisture-free state is maintained by opening the gate valve. 2 . The method of forming an aluminum oxide film according to claim 1 , wherein the moisture removal trap is installed in front of the turbo pump of the discharge line. 3 .

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