OLED (Organic Light Emitting Diode) evaporation film layer thickness on-line measuring device

Abstract

The utility model relates to the technical field of OLED display device manufacturing, and discloses an OLED evaporation film layer thickness on-line measuring device which comprises a vacuum chamber, a measuring lens, a substrate, an evaporation film layer, a chamber alignment mechanism, an electrostatic chuck and an auxiliary top PIN which are arranged in the vacuum chamber, and a spectrograph and a light source which are arranged outside the vacuum chamber, the evaporation film layer is deposited on the substrate, the substrate is supported on the chamber alignment mechanism, the measuring lens is located below the evaporation film layer, the spectrograph and the light source are connected with the measuring lens through optical fibers, the electrostatic chuck is used for adsorbing the substrate, and the auxiliary top PIN is used for jacking the substrate. According to the utility model, the thickness of each evaporation film layer can be measured on line, the electrostatic chuck is adopted to adsorb the back surface of the substrate, and after the glass substrate is completely adsorbed to be flat, the thickness measurement of the evaporation film is completed, so that the problem that the SR cannot be measured due to the sagging of the substrate due to gravity is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of OLED display device manufacturing, in particular to an online measurement device for the thickness of an OLED evaporated film layer. Background Art

[0002] As the core process of the OLED panel display industry, the evaporation process plays a decisive role in the production yield of the entire panel. The function of the evaporation machine is to evaporate the luminescent material and other functional materials to a specific position of the target substrate in an ultra-high vacuum environment by heating. Due to the special principle of OLED luminescence, the film deposited on the substrate is particularly thin, with a thickness of approximately 0.1nm-12nm. In addition, the accuracy of the deposited film on the substrate is particularly important for OLED light-emitting devices. How to control the accuracy and stability of the film thickness in the production process is the most important factor for the success of the device.

[0003] Since the luminescent materials and functional materials used in OLED light-emitting devices are easily oxidized by water, oxygen or other gases, the industry uses optical non-contact methods to measure the thickness of the film. The mature method is to use ellipsometer (SE) to measure the thickness of the film. The SE measurement principle is that the incident light irradiates the surface of the film at 45°, and the light reflected by the substrate after passing through the film is emitted to the lens at 45°. After the light passes through the film, the phase angle of the light wave changes. The magnitude of the change is a function of the film thickness, and the thickness of the film can be obtained by fitting. Therefore, the SE measurement method requires two 45° lenses to complete the collection of spectral information, and the object to be measured must be placed on a marble work surface during measurement, and the vibration of the equipment will also affect the measurement accuracy. Therefore, the traditional SE measurement must make a precise measuring device. In order to protect the measured product from being affected by water, oxygen or other gas components, and because the measurement environment requires as little vibration as possible, an ultra-high vacuum atmosphere cannot be used, and only a pure nitrogen environment or other inert gas environment can be used, which also leads to a huge cost for SE measurement.

[0004] At the same time, since the thin film deposition adopts a vacuum environment and the measurement adopts the nitrogen environment of the SE equipment, the chamber atmosphere needs to be replaced when the product interacts with the chamber before measurement. This determines that it takes a long time to measure the product once. Therefore, the current solution is to only conduct random inspections on the deposited film thickness, and cannot monitor the film thickness of each product online, which is very likely to cause defective products.

[0005] The invention patent with publication number CN115702485A discloses a solution for in-situ measurement of thin films by processing transparent crystals and transparent substrates in the chamber wall. This solution can monitor the thickness of the deposited film in real time. However, for large-size substrates used in the production process of OLED display panels, the deformation of the substrate due to its own weight causes the measurement process to no longer be an ideal mirror reflection, and the measurement lens will be unable to measure, affecting the accuracy of the measurement. Utility Model Content

[0006] In view of the problems and defects existing in the above-mentioned prior art, the utility model provides an online measurement device for the thickness of OLED evaporated film layer, which adopts reflectance spectroscopy to detect the thickness of the evaporated film layer of the OLED panel, and adopts an electrostatic suction cup to solve the problem of substrate sagging and deformation due to weight. The measurement unit is integrated in the vacuum chamber to realize the film thickness detection of each product.

[0007] In order to achieve the above utility model purpose, the technical solution of the utility model is as follows:

[0008] The utility model provides an online measurement device for the thickness of an OLED evaporated film layer, the device mainly comprising: a vacuum chamber, wherein a measuring lens, a substrate and an evaporated film layer are arranged in the vacuum chamber, and a spectrometer and a light source connected to the measuring lens are arranged outside the vacuum chamber; wherein the evaporated film layer is deposited on the substrate, the measuring lens is located below the evaporated film layer, and the spectrometer and the light source are connected to the measuring lens in the chamber through an optical fiber; further, the device further comprises:

[0009] A chamber alignment mechanism disposed in the vacuum chamber for supporting the substrate;

[0010] An electrostatic chuck disposed in the vacuum chamber for adsorbing the substrate; and,

[0011] An auxiliary lifting PIN is arranged in the vacuum chamber for lifting the substrate.

[0012] The auxiliary top PIN lifts the substrate on the chamber alignment mechanism upward until it contacts the electrostatic suction cup above, and the suction cup adsorbs the back side of the substrate; during the test, the measuring lens vertically incidents the light beam from the light source onto the measuring point of the evaporated film layer, and receives the light reflected from the surface of the film and the light reflected from the surface of the substrate, focuses it and transmits it to the spectrometer outside the chamber through the optical fiber; further, the spectrometer converts the signal intensity of the spectrum into an electrical signal, and transmits it to a data processing device such as a computer connected thereto through a communication line to obtain the thickness value of the evaporated film layer.

[0013] As a preferred solution of the utility model, the auxiliary top PIN is arranged on the chamber alignment mechanism.

[0014] As a preferred solution of the utility model, the measuring lens is located on the chamber alignment mechanism.

[0015] As a preferred solution of the utility model, the electrostatic chuck is provided with an ESC alignment mechanism, and the output end of the electrostatic chuck alignment mechanism extends into the vacuum chamber and is connected to the electrostatic chuck.

[0016] As a preferred solution of the utility model, a magnetic fluid sealing unit is provided between the output end of the ESC alignment mechanism and the vacuum chamber.

[0017] As a preferred solution of the utility model, the vacuum chamber is provided with an optical fiber feed-through coupling flange for the optical fiber to pass through.

[0018] As a preferred solution of the utility model, the device also includes a suction cup controller, the electrostatic suction cup is connected to the suction cup controller outside the vacuum chamber through a control line, and a vacuum feedthrough flange for the control line to pass through is provided on the shell of the vacuum chamber.

[0019] Beneficial effects of the utility model:

[0020] 1. The utility model sets the measuring lens in a vacuum chamber that is the same as the deposition environment, and does not need to change the atmosphere in the chamber. The thickness of each evaporated film layer can be measured online, which reduces costs and reduces measurement time.

[0021] 2. The utility model adopts an electrostatic suction cup to absorb the back of the substrate. After the glass substrate is completely sucked flat, the ESC alignment mechanism carries the substrate for alignment. After the alignment is completed, the online measurement of the thickness of the evaporated film can be realized, which solves the problem that the measurement lens cannot measure due to the deformation of the substrate due to gravity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and following detailed description of the present invention will become more clear when read in conjunction with the following drawings, in which:

[0023] Figure 1 This is a schematic diagram of the online measuring device of the utility model;

[0024] Figure 2-Figure 5 This is a schematic diagram of the process of auxiliary PIN lifting and electrostatic chuck adsorbing substrate in the utility model;

[0025] Figure 6-Figure 7 This is a schematic diagram of the substrate resetting process of the utility model.

[0026] In the figure:

[0027] 1. Vacuum chamber; 2. Chamber alignment mechanism; 3. Measuring lens; 4. Substrate; 5. Spectrometer; 6. Auxiliary top PIN; 7. Electrostatic chuck; 8. ESC alignment mechanism; 9. Magnetic fluid sealing unit; 10. Fiber feedthrough coupling flange; 11. Suction cup controller; 12. Vacuum feedthrough flange; 13. Data processing equipment. DETAILED DESCRIPTION

[0028] Since the luminescent materials and functional materials used in OLED light-emitting devices are easily oxidized by water, oxygen or other gases, the industry uses optical non-contact methods to measure the thickness of the film. The mature method is to use ellipsometer (SE) to measure the thickness of the film. The SE measurement principle is that the incident light irradiates the surface of the film at 45°, and the light reflected by the substrate after passing through the film is emitted to the lens at 45°. After the light passes through the film, the phase angle of the light wave changes. The magnitude of the change is a function of the film thickness, and the thickness of the film can be obtained by fitting. Therefore, the SE measurement method requires two 45° lenses to complete the collection of spectral information, and the object to be measured must be placed on a marble work surface during measurement, and the vibration of the equipment will also affect the measurement accuracy. Traditional SE measurement requires a precise measuring device to be made. In order to protect the measured product from being affected by water, oxygen or other gas components, and because the measurement environment requires as little vibration as possible, an ultra-high vacuum atmosphere cannot be used, and only a pure nitrogen environment or other inert gas environment can be used. This results in a huge cost for SE measurement.

[0029] At the same time, since the thin film deposition adopts a vacuum environment and the measurement adopts the nitrogen environment of the SE equipment, the chamber atmosphere needs to be replaced when the product interacts with the chamber before measurement. This determines that it takes a long time to measure the product once. Therefore, the current solution is to only conduct random inspections on the deposited film thickness, and cannot monitor the film thickness of each product online, which is very likely to cause defective products.

[0030] Based on this, the utility model proposes a new online measurement device for the thickness of OLED evaporated film. The utility model adopts the method of vertical light incidence. The detection beam output by the light source is incident on the surface of the film at a vertical angle of 90°. After the light passes through the surface of the film, the light is reflected back at the substrate surface. The coupled light spectrum information of the film reflected light and the substrate reflected light is obtained through spectrometer analysis, and the film thickness of the film can be fitted. For detailed theory, please refer to the principle of measuring thin films by reflection spectroscopy. Since it adopts 90° optical signal transmission, the incident light and reflected light lenses can be integrated together. The lens is integrated into the vacuum chamber by designing the lens mechanism. Finally, the spectral signal obtained by the measurement lens in the vacuum chamber is transmitted to the spectrometer outside the vacuum chamber through optical fiber, so that the film thickness can be fitted.

[0031] This utility model uses reflectance spectroscopy to detect the thickness of the evaporated film layer in the OLED panel industry, and uses an electrostatic chuck (hereinafter referred to as ESC) to solve the problem of the substrate sagging due to weight. The measurement unit is integrated in the vacuum chamber, and the film thickness detection of each product can be realized. The specific scheme is as follows:

[0032] Refer to the instruction manual Figure 1 As shown, it is a schematic diagram of the structure of an example measuring device of one aspect of the disclosure of the utility model, the device mainly comprises a vacuum chamber 1, a measuring lens 3, a substrate 4 and a vapor-deposited film layer arranged in the vacuum chamber 1, and a spectrometer and a light source arranged outside the vacuum chamber 1; wherein the vapor-deposited film layer is deposited on the substrate 4, the measuring lens 3 is located directly below the vapor-deposited film layer, and the spectrometer 5 and the light source are connected to the measuring lens 3 in the chamber through an optical fiber; further, the measuring device also comprises:

[0033] A chamber alignment mechanism 2, wherein the chamber alignment mechanism 2 is disposed in the vacuum chamber 1 and is used to support a substrate 4 on which a vapor-deposited film layer is deposited;

[0034] An electrostatic chuck 6, which is disposed in the vacuum chamber 1 and above the substrate 4, and is used to absorb the substrate 4;

[0035] The auxiliary lifting PIN 7 is arranged in the vacuum chamber 1 and is located below the substrate 4 , and is used to lift the substrate 4 supported by the chamber alignment mechanism 2 .

[0036] In the depicted embodiment, the chamber alignment mechanism 2 uses four top pillars arranged on the top surface to contact the four corners of the substrate 4 respectively in a four-point support manner, thereby supporting and fixing the substrate 4.

[0037] In the depicted embodiment, the measuring lens 3 and the auxiliary top PIN 7 are arranged on the chamber alignment mechanism 2 ; wherein the auxiliary top PIN 7 is distributed at the four corners of the substrate 4 .

[0038] In various implementations of the present invention, the light source and the spectrometer 5 may be packaged together in an integrated structure to form a whole, or may be separate structures, and the present invention does not make any special limitation thereto.

[0039] In various embodiments of the utility model, the chamber alignment mechanism 2 generally also has a displacement adjustment function, which can adjust the position of the substrate 4 supported thereon in the chamber, thereby achieving an alignment effect. The displacement adjustment includes horizontal displacement adjustment in the front and back and left and right directions and vertical displacement adjustment in the vertical direction. It should be noted that the chamber alignment mechanism 2 can use an existing three-dimensional motion platform to achieve its displacement adjustment function. The three-dimensional motion platform is a prior art and will not be described in detail here. In the depicted embodiment, the chamber alignment mechanism 2 is generally mounted on the bottom wall of the vacuum chamber 1.

[0040] In the present invention, because the evaporation process mostly adopts a bottom-up deposition method, the measuring lens 3 is installed directly below the evaporated film layer. The function of the lens is to accurately incident the emitted light of the light source on the measuring point of the film layer on the substrate after focusing the lens, and transmit the reflected light information of the spectrum to the spectrometer through the lens. The spectrometer converts the signal intensity of the spectrum into an electrical signal and transmits it to the computer. The spectral intensity signal is fitted by the relevant film thickness fitting algorithm to obtain the thickness value of the evaporated film layer. In the depicted embodiment, the film thickness fitting algorithm fitting the spectral intensity signal is a prior art and will not be elaborated in detail here.

[0041] Furthermore, in the present invention, since the measuring lens 3 is in the vacuum chamber 1, and the spectrometer 5 and the light source are both in the atmospheric environment, it is necessary to use a vacuum sealing flange to achieve the transmission of the spectral signal through the optical fiber feedthrough. That is, in the present invention, the side wall of the vacuum chamber 1 is provided with an optical fiber feedthrough coupling flange 10 for the optical fiber to pass through, and the optical fiber is connected to the measuring lens 3 in the chamber after passing through the flange.

[0042] Furthermore, in the present invention, the electrostatic suction cup 6 is usually installed on the top wall of the chamber, connected to the suction cup controller 11 outside the vacuum chamber 1 through a control line, and a vacuum feedthrough flange 12 is provided on the top wall of the vacuum chamber 1 for the control line to pass through.

[0043] In the present invention, in order to better and more accurately measure the film thickness, so that the outgoing light beam output by the light source can be correctly incident on the measuring point of the film, the electrostatic chuck is also provided with an ESC alignment mechanism 8, and the output end of the alignment mechanism extends into the vacuum chamber 1 and is connected to the electrostatic chuck 6. The ESC alignment mechanism 8 can adjust the electrostatic chuck 6 in the chamber in terms of front-back and left-right horizontal displacement, vertical displacement adjustment, and drive the electrostatic chuck 6 to rotate in the horizontal direction, thereby adjusting its angle, and finally achieving the effect of aligning the substrate 4.

[0044] In some embodiments, a magnetic fluid sealing unit 9 is provided between the output end of the ESC alignment mechanism 8 and the vacuum chamber. The function of the magnetic fluid sealing unit 9 is to transfer the rotational motion into the sealed container, and is often used for vacuum sealing.

[0045] In the present invention, in order to reduce costs and increase production capacity, the size of the substrate is generally as large as possible. Glass is usually used as the substrate, and the glass substrate is very thin. Since the middle of the glass is the display area of ​​the film layer and cannot be directly contacted, a blank area is left at the edge of the glass, and the substrate is placed horizontally on the top column of the chamber alignment mechanism 2. However, since the substrate cannot be supported on the front, the glass is deformed. However, according to the principle of measuring film thickness by reflected light, the reflected light must be irradiated vertically to receive the spectral signal. Therefore, the present invention uses an electrostatic suction cup 6 to absorb the back side of the substrate (the side without the evaporated film layer). After the glass substrate is completely sucked flat, the ESC alignment mechanism 8 carries the substrate for alignment. After the alignment is completed, the measurement can be achieved.

[0046] Refer to the instruction manual Figure 2-7 , is a schematic diagram of the specific measurement process of the measuring device. During the test, the main process is as follows:

[0047] Step 1. Refer to the instruction manual Figure 2 As shown, the product is moved from the process chamber into the vacuum chamber 1 and aligned by the chamber alignment mechanism 2 in the chamber. During the alignment process, the ESC (electrostatic chuck 6) descends.

[0048] Step 2. Refer to the instruction manual Figure 3 As shown, at this time, the auxiliary top PIN 7 rises to lift the glass substrate and contact it with the ECS, and the ESC is energized to start adsorbing the glass substrate.

[0049] It is particularly important to note that when ESC adsorbs the substrate, it can only slowly adsorb the glass upward from one side. If the two sides of the glass are adsorbed first during the adsorption process, the glass substrate will deform toward the middle due to the two sides, which will cause glass fragments.

[0050] Step 3. Refer to the instruction manual Figure 4 As shown, the auxiliary top PIN 7 descends, and the ESC adsorbs the glass substrate for alignment.

[0051] Step 4. Refer to the instruction manual Figure 5 As shown, after the ESC alignment is completed, the measuring lens 4 collects the light signal and transmits the signal to the spectrometer through the optical fiber for measurement.

[0052] Step 5. After the measurement is completed, the auxiliary top PIN 7 rises and is connected back to the glass substrate. During this process, the top PINs on both sides can rise at the same time.

[0053] Step 6. The electrostatic chuck 6 rises, and the equipment takes over the machine alignment and waits for the glass substrate to be moved out.

[0054] After the above process, during the measurement process, the detection light beam output by the light source is vertically incident on the surface of the film through the measuring lens, and then the reflected light is also vertically irradiated into the measuring lens. Therefore, the problem of being unable to measure due to the measurement lens being unable to receive the light signal caused by the large-size substrate sagging and deforming under the action of gravity can be solved.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0056] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] The above is only a preferred embodiment of the present application and does not constitute any form of obstruction to the present application. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present application shall fall within the protection scope of the present application.

Claims

1. An online measuring device for the thickness of an OLED evaporated film, comprising: A vacuum chamber (1), a measuring lens (3), a substrate (4) and a vapor-deposited film layer arranged in the vacuum chamber (1), and a spectrometer (5) and a light source arranged outside the vacuum chamber (1); wherein the vapor-deposited film layer is deposited on the substrate (4), the measuring lens (3) is located below the vapor-deposited film layer, and the spectrometer (5) and the light source are connected to the measuring lens (3) via an optical fiber, and characterized in that it also includes: A chamber alignment mechanism (2) disposed in the vacuum chamber (1) and used for supporting a substrate (4); an electrostatic chuck (6) disposed in the vacuum chamber (1) for adsorbing the substrate (4); and An auxiliary lifting PIN (7) is arranged in the vacuum chamber (1) and is used for lifting the substrate (4).

2. The online measuring device for the thickness of an OLED evaporated film according to claim 1, characterized in that: The auxiliary top PIN (7) is arranged on the chamber alignment mechanism (2).

3. The online measuring device for the thickness of an OLED evaporated film according to claim 1, characterized in that: The measuring lens (3) is located on the chamber alignment mechanism (2).

4. The online measuring device for the thickness of an OLED evaporated film according to claim 1, characterized in that: The electrostatic chuck (6) is provided with an ESC alignment mechanism (8), and an output end of the ESC alignment mechanism (8) extends into the vacuum chamber (1) and is connected to the electrostatic chuck (6).

5. The online measuring device for the thickness of an OLED evaporated film according to claim 4, characterized in that: A magnetic fluid sealing unit (9) is provided between the output end of the ESC alignment mechanism (8) and the vacuum chamber (1).

6. The online measuring device for the thickness of an OLED evaporated film according to claim 1, characterized in that: The vacuum chamber (1) is provided with an optical fiber feed-through coupling flange (10) for the optical fiber to pass through.

7. The online measurement device for the thickness of an OLED evaporated film according to claim 1, characterized in that: The electrostatic chuck (6) is connected to a chuck controller (11) outside the vacuum chamber (1) via a control line, and a vacuum feed-through flange (12) is provided between the vacuum chamber (1) and the control line.

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