KR20060039263A - Apparatus for depositing organic thin layer that can detect the thickness of the organic thin layer in real time and method thereof - Google Patents

Abstract

The present invention relates to an organic thin film deposition apparatus for manufacturing an organic light emitting device (OLED), and more particularly, to an organic thin film deposition apparatus capable of monitoring in real time the film thickness deposited on a substrate.

The present invention is disposed in the vacuum chamber in the same conditions as the substrate on which the organic thin film is inspected, the test substrate is arranged so that the thickness of the organic thin film deposited on the test substrate on which the organic thin film is deposited on its surface can be measured in real time. The information obtained by irradiating the laser onto the test substrate is Fourier transformed in real time so that the thickness of the organic thin film deposited on the substrate can be measured in real time.

Organic light emitting diode, organic thin film, thickness measurement, laser, Fourier transform

Description

Organic thin film deposition apparatus and organic thin film deposition method capable of measuring the thickness of the organic thin film deposited in real time {APPARATUS FOR DEPOSITING ORGANIC THIN LAYER THAT CAN DETECT THE THICKNESS OF THE ORGANIC THIN LAYER IN REAL TIME AND METHOD THEREOF}

1 is a schematic diagram showing the structure of an OLED.

2 is a cross-sectional view showing the structure of a conventional organic thin film deposition apparatus.

3 is a cross-sectional view showing the structure of an organic thin film deposition apparatus according to an embodiment of the present invention.

Figure 4 is an exploded perspective view showing the structure of the film thickness monitoring unit according to an embodiment of the present invention.

5 is a view for explaining a process of generating a path difference while the laser is reflected from the test substrate.

6 is a graph showing data on the film thickness obtained in the present invention.

7 is a graph showing the results of Fourier transforming data on the film thickness obtained in the present invention.

8 is a process chart showing a process of an organic thin film deposition method according to an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

1: conventional organic thin film deposition apparatus

100: organic thin film deposition apparatus according to an embodiment of the present invention

10, 110: vacuum chamber 20, 120: substrate holder

30, 130: organic material evaporation source 50: sensor

140: film thickness monitoring unit 150: laser unit

S: Substrate M: Mask

TS: Test Substrate OL: Organic Thin Film

The present invention relates to an organic thin film deposition apparatus for manufacturing an organic light emitting device (OLED), and more particularly, to an organic thin film deposition apparatus capable of monitoring in real time the film thickness deposited on a substrate.

Recently, with the rapid development of information and communication technology and the expansion of the market, flat panel displays have been in the spotlight as display devices. Such flat panel displays include liquid crystal displays, plasma display panels, organic light emitting diodes, and the like.

 Among them, organic light emitting diodes have not only fast response speed, lower power consumption and lighter weight than conventional liquid crystal display devices, but also can be made ultra-thin because there is no need for a separate back light device. It has a merit as a next generation display device.

In the organic light emitting device, an anode film, an organic thin film, and a cathode film are sequentially coated on a substrate, and a suitable energy difference is formed in the organic film by emitting voltage between the anode and the cathode, thereby emitting light by itself. That is, the excitation energy left by recombination of injected electrons and holes is generated as light. In this case, since the wavelength of light generated according to the amount of the dopant of the organic material may be adjusted, full color may be realized.

Detailed structure of the organic light emitting device is shown in Figure 1, the anode (hole), hole injection layer (hole injection layer), hole transfer layer (hole transfer layer), light emitting layer (emitting layer), electron transport layer on the substrate The eletron transfer layer, the electron injection layer, and the cathode are sequentially stacked. In this case, ITO (Indium Tin Oxide) having a small sheet resistance and good permeability is mainly used as the anode. The organic thin film is composed of a multilayer of a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injection layer in order to increase luminous efficiency. The organic materials used as the light emitting layer are Alq ₃ , TPD, PBD, m-MTDATA, TCTA. As the cathode, a LiF-Al metal film is used. In addition, since the organic thin film is very weak to moisture and oxygen in the air, an encapsulation film is formed on the top to increase the life time of the device.

Among the various layers described above, the organic thin film is the most important component, and the organic thin film is deposited by an organic thin film deposition apparatus for depositing a thin film by a thermal deposition method, which is a kind of physical vapor deposition method.

As shown in FIG. 2, the substrate holder 20 is disposed on the chamber 10 in the conventional light emitting organic thin film deposition apparatus 1. Then, the substrate S is mounted on the substrate holder 20, and the shadow mask M is placed in close contact with the substrate S. The organic material evaporation source 30 is disposed below the chamber 10, and the organic material is evaporated and sent to the upper side of the chamber. Therefore, when the organic material evaporation source 30 evaporates the organic material under the chamber 20, the organic material vapor is diffused and deposited on the substrate mounted on the substrate holder 20.

At this time, the sensor 50 is provided in the chamber 20 to monitor the thickness of the film deposited on the substrate (S). The sensor 50 is disposed between the organic material evaporation source 30 and the substrate S to monitor the amount of diffused organic vapor and detect the thickness of the film indirectly deposited on the substrate.

However, this monitoring method is an indirect method that does not actually measure the thickness of the film deposited on the substrate, so the accuracy is low, and there is a problem in that information about the film thickness cannot be monitored in real time.

An object of the present invention is to provide an organic thin film deposition apparatus having a film thickness monitoring unit that can measure the thickness of the film deposited on the substrate in real time.

Another object of the present invention is to provide an organic thin film deposition method capable of measuring the thickness of a film deposited on a substrate in real time.

The present invention to achieve the above object, the vacuum chamber capable of forming a vacuum therein; A substrate holder provided on an upper side of the chamber and coupling the substrate to a lower surface thereof; An organic material evaporation source provided below the chamber and evaporating the organic material above the chamber; A film thickness monitoring unit provided adjacent to the substrate holder and having a test substrate coupled thereto; A laser unit provided under the chamber, for irradiating a laser onto the test substrate and detecting a reflected laser; It provides an organic thin film deposition apparatus comprising a; display unit for converting the information obtained from the laser unit to show in real time.

And in the present invention, the film thickness monitoring unit, a test substrate joining table coupled to the lower surface of the plurality of test substrates; A blocking unit disposed in close contact with the test substrate at a lower side of the test substrate combiner and blocking a remaining portion of the test substrate combiner exposing any one of a plurality of test substrates; Rotating the substrate coupler or the blocking portion to expose the other test substrate to be configured to include, thereby measuring the film thickness deposited on the substrate in real time.

In the present invention, by combining the test substrate with a substrate of the same material as the substrate that is actually bonded to the substrate holder, to obtain the same effect as directly measuring the thickness of the film deposited on the substrate.

In the present invention,

1) placing the test substrate at the same height as the substrate on which the organic material is deposited;

2) evaporating and depositing an organic material under the substrate and the test substrate;

3) irradiating a laser onto the surface of the test substrate at the lower side of the test substrate at the same time as the step 2) and receiving the reflected light to collect information;

4) provides a method for measuring the thickness of the organic material comprising; converting and displaying the information obtained in step 3).

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

Organic thin film deposition apparatus 100 according to the present embodiment, the vacuum chamber 110; Substrate holder 120; Organic material evaporation source 130; Film thickness monitoring unit 140; Laser unit 150; It is configured to include a display unit (not shown in the figure).

Here, the vacuum chamber 110, the substrate holder 120, and the organic material evaporation source 130 perform the same structure and function as those of the conventional organic thin film deposition apparatus 1, and thus are not repeated here.

In this embodiment, the film thickness monitoring unit 140 is a component for placing a test substrate to measure the thickness of the organic thin film deposited on the substrate by evaporation from the organic material evaporation source 130. In this embodiment, the film thickness monitoring unit 130, as shown in Figure 3, is provided adjacent to the substrate holder 120, so that the test substrate is coupled to the lower surface.

At this time, the film thickness monitoring unit 140, as shown in Figure 4, the test substrate coupling table 142; Blocking unit 144; Rotating portion 146; consists of. Here, the test substrate joining table 142 is a member to which a test substrate is attached, and in this embodiment, a plurality of test boards are disposed at predetermined intervals on the test board joining table 142. Therefore, when one test substrate is used to some extent and an organic thin film is deposited on the surface thereof, and it is no longer available, the next test substrate is used to shorten the process time by prolonging the replacement cycle of the test substrate.

Next, the film thickness monitoring unit 140 according to the present embodiment further includes a blocking unit 144 that exposes only one of the plurality of test substrates coupled to the test substrate coupler 142 and blocks the other test substrates. It is preferable to provide. As shown in FIG. 4, the blocking unit 144 is provided such that only one of the plurality of test substrates TS coupled to the test substrate coupler 142 is exposed downward.

Next, the rotating unit 146 rotates the test substrate coupler 142 or the blocking unit 144 to block the test substrate which has reached the end of its life and expose a new test substrate.

In this embodiment, the test substrate TS is made of the same material as the actual substrate S coupled to the substrate holder 120. In addition, the height of the test substrate coupler 142 is preferably disposed at the same height as the substrate holder 142 so that the test substrate TS is located at the same height as the substrate S. Therefore, in this embodiment, the test substrate is deposited under the same conditions as the actual substrate. Therefore, the thickness of the organic thin film deposited on the test substrate is equal to the thickness of the thin film deposited on the substrate.

Next, the laser unit 150 is a component that collects information on the thickness of the thin film deposited on the surface of the test substrate by receiving the reflected light by irradiating the laser on the surface of the test substrate TS. In this embodiment, the laser unit 150 is provided below the chamber 110, the laser is irradiated upward, and the light reflected from the test substrate TS can be received. In this embodiment, the laser unit 150 irradiates a laser having a wavelength of 630 nm. Accordingly, in the laser unit 150, as shown in FIG. 5, the path difference between the light L1 reflected from the surface of the organic thin film OL and the light L2 reflected from the surface of the test substrate TS. By this, information of a pattern in which interference occurs is obtained.

Next, the display unit is a component that displays information in real time by switching information on the film thickness obtained from the laser unit. In this embodiment, the display unit Fourier transform (Fourier Transformation) the information transmitted from the laser unit in real time to show the thickness of the organic material deposited on the test substrate.

Fourier transforms are basically used to convert signals in the time domain to signals in the frequency domain and vice versa. Here, the signal in the time domain represents how the signal changes with time, and the signal in the frequency domain expresses how many frequencies the signal has and the signals in both domains are displayed in two dimensions. For signals in the time domain, the Y axis is often the magnitude of the signal and the X axis is time. On the other hand, for signals in the frequency domain, the Y axis represents the magnitude and phase of the signal, and the X axis represents the frequency of the signal.

In this embodiment, the information obtained by the laser unit 150 is shown in FIG. 5, the light irradiated from the laser unit 150 is reflected from the surface of the organic thin film (OL) deposited on the surface of the test substrate After passing through the light L1 and the organic thin film, information by interference of light L2 reflected from the surface of the test substrate TS is obtained. As shown in FIG. 6, information of a pattern in which light intensity periodically changes with time is obtained. Accordingly, the signal obtained by the laser unit is a signal in the time domain, and the signal is Fourier transformed by the display unit to convert the signal into a signal in the frequency domain as shown in FIG. 7.

In this embodiment, a Fast Fourier Transformation program that performs Fourier transform in real time is used to obtain information about the film thickness in real time.

Hereinafter, a method of measuring organic material thickness according to the present embodiment will be described.

First, a step (P10) of placing the test substrate on the test substrate combiner is performed. In this step, a plurality of test substrates are spaced apart at predetermined intervals on the test substrate combiner.

Next, the organic material is deposited on the substrate by applying heat to the organic material evaporation source to evaporate (P20). In this step, the organic material is deposited not only on the substrate but also on the surface of the test substrate under the same conditions as the substrate.

Next, a step (P30) of collecting information on the thickness of the organic thin film deposited on the test substrate is performed by irradiating a laser onto the test substrate surface. This step proceeds with the organic material deposition step (P20) from the step of starting to deposit the organic material on the substrate. Therefore, in this embodiment, the situation in which the organic material is deposited on the substrate is measured in real time to collect information about it.

Next, a step (P40) of converting and displaying the information obtained in the laser irradiation and light receiving step (P30) is performed. In this step, Fourier transform information obtained by using the reflection pattern of the laser irradiated on the test substrate in real time and display the result.

According to the present invention, since the test substrate is placed under the same conditions as the actual substrate and the thickness of the organic thin film deposited on the test substrate is monitored in real time, the same effect as measuring the thickness of the organic thin film deposited on the actual substrate can be obtained. .

In particular, in the present invention, by continuously irradiating the laser in the deposition process to obtain information about the thickness of the thin film deposited on the test substrate continuously, the Fourier transform in real time and display it can monitor the thin film deposition pattern on the substrate in real time There is an advantage.

Claims (9)

A vacuum chamber capable of forming a vacuum therein; A substrate holder provided on an upper side of the chamber and coupling the substrate to a lower surface thereof; An organic material evaporation source provided below the chamber and evaporating the organic material above the chamber; A film thickness monitoring unit provided adjacent to the substrate holder and having a test substrate coupled thereto; A laser unit provided under the chamber, for irradiating a laser onto the test substrate and detecting a reflected laser; Organic display device comprising a; display unit for converting the information obtained from the laser to display in real time. The method of claim 1, wherein the film thickness monitoring unit, A test substrate joining table in which a plurality of test substrates are coupled to a bottom surface of the test substrate; A blocking unit disposed in close contact with the test substrate at a lower side of the test substrate combiner and blocking a remaining portion of the test substrate combiner exposing any one of a plurality of test substrates; And a rotating part for rotating the substrate coupler or the blocking part to expose the other test substrate. The test substrate according to any one of claims 1 to 3, wherein the test substrate is Organic thin film deposition apparatus, characterized in that the same material as the substrate coupled to the substrate holder. The test substrate according to any one of claims 1 to 3, wherein the test substrate is Organic thin film deposition apparatus, characterized in that located at the same height as the substrate coupled to the substrate holder. The laser unit of claim 1 or 2, wherein the laser unit is An organic thin film deposition apparatus characterized by irradiating a laser having a wavelength of 630nm. The display unit of claim 1, wherein the display unit comprises: Organic thin film deposition apparatus characterized by showing the thickness of the organic material deposited on the test substrate in real time by Fourier transform (Fourier Transformation) the information transmitted from the laser unit. 1) placing the test substrate at the same height as the substrate on which the organic material is deposited; 2) evaporating and depositing an organic material under the substrate and the test substrate; 3) irradiating a laser onto the surface of the test substrate at the lower side of the test substrate at the same time as the step 2) and receiving the reflected light to collect information; 4) converting and displaying the information obtained in the step 3); organic thin film deposition method comprising a. The method of claim 7, wherein in step 3), An organic thin film deposition method characterized by irradiating a laser having a wavelength of 630nm. The method of claim 7, wherein in step 4), The organic thin film deposition method of claim 3, wherein the interference information of the laser beam obtained in step 3 is displayed in real time by Fourier Transformation.

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