Method for manufacturing organic light-emitting

Abstract

To provide an electron beam etching method for reducing a pixel size of an organic light emitting diode which reduces the pixel size to several hundred nanometers.SOLUTION: By introducing an electron beam lithography process method, an evaporation method through a fine metal mask in the manufacture of an existing organic light-emitting diode display screen is abandoned, and an insulating electron beam resist is used as a fixed mask, thereby avoiding thermal expansion and cold shrinkage of a material and a positioning error when the fine metal mask is moved or replaced. The process includes step (4) of etching a blind hole structure in an electron beam resist, step (5) of increasing a surface work function of a conductive anode on a substrate, and step (6) of evaporating each organic functional layer and a conductive cathode of an organic light-emitting diode on the electron beam resist having the blind hole structure to prepare the organic light-emitting diode with a pixel size of hundreds of nanometers.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the field of improvements in the manufacturing process of organic light emitting diodes, and more particularly to an electron beam etching method for reducing the pixel size of organic light emitting diodes. [Background technology]

[0002] Organic light-emitting diodes (OLEDs) are electroluminescent devices formed by stacking organic thin film structures. As the third generation display technology following CRT and LCD displays, they have become a research hotspot in the display field due to their advantages of being all-solid-state, self-luminous, low power consumption, high contrast, high brightness, high resolution, large display area, wide viewing angle, short response time, ultra-thin, and flexible. The development of the ultra-high-definition video industry depends heavily on display technology, and ultra-high resolution is required for ultra-high-definition video display.

[0003] Currently, the industry's majority of OLED display screen manufacturing uses a fine metal mask deposition method, which separates deposition materials using a movable fine metal mask to form the red, green, and blue primary color pixels of OLEDs. However, due to factors such as the shadow effect of the evaporative coating, the precision of the aperture size and positioning of the fine metal mask, the thermal expansion and contraction of the material, and positioning errors when moving or replacing the fine metal mask (all of which are on the micron level), OLED size is difficult to further shrink after being reduced to a few microns. While there are reports of OLEDs being reduced to approximately 1 micron using electron beam etching, this method introduces more complex structures and does not fully utilize the advantage of the small minimum line width of the electron beam etching process, making it impossible to further reduce the pixel size of OLEDs to several hundred nanometers.

[0004] To solve this problem, a paper in the journal Science, Vol. 370, Issue 6515, 2020, pp. 459-463, reported that electron beam etching and reactive ion etching processes were used to reduce the pixel size of organic light-emitting diodes to 1.2 microns by 1.2 microns, achieving ultra-high pixel density (>10,000 pixels per inch), eliminating the reliance on fine metal masks, and significantly reducing the shadow effect of evaporated coatings. However, the process involves the introduction of nanopatterned metasurface reflectors (Fabry-Perot cavities), which limits the further reduction in the size of organic light-emitting diodes using electron beam etching. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an electron beam etching method for reducing the pixel size of an organic light-emitting diode, which simplifies the structure of the organic light-emitting diode and reduces the pixel size to several hundred nanometers by using an electron beam etching method and improving the etching process steps. [Means for solving the problem]

[0006] The present invention provides an electron beam etching method for reducing pixel size of an organic light emitting diode, the method comprising: (1) cleaning the substrate; (2) sputtering a conductive anode onto a substrate; (3) spin-coating an electron beam resist onto a conductive anode; (4) etching a blind hole structure in the electron beam resist; (5) increasing the surface work function of a conductive anode on the substrate; and (6) depositing a hole transport layer, a light-emitting layer and electron transport layer, and a cathode of the organic light-emitting diode onto the electron beam resist to fabricate the organic light-emitting diode.

[0007] Preferably, in the specific procedure of step (1), the substrate is first thoroughly washed, then immersed in ultrapure water, acetone, isopropanol, and ultrapure water in that order for 15 to 20 minutes each, and while immersed, the substrate is cleaned in an ultrasonic bath, and finally dried by spraying compressed gas onto the substrate.

[0008] Preferably, the substrate in step (1) is a transparent insulating substrate.

[0009] Preferably, the conductive anode in step (2) is indium tin oxide (ITO).

[0010] Preferably, in the specific procedure of step (2), first, a pre-cleaned substrate is placed in the chamber of a magnetron sputtering coating device, the sputtering surface of the substrate is placed downward and fixed on a sample tray, the ITO target material to be sputtered is placed at the sputtering source position of the magnetron sputtering coating device, then a mechanical pump is started to pre-evacuate the sample chamber to control the vacuum level in the sample chamber to 10 Pa or less, and then a molecular pump is started to evacuate the chamber to 1×10 -5 The chamber is evacuated to a pressure of 100 Pa or higher, and finally, the AC sputtering source is started. The rotation speed of the sample tray on which the substrate is placed is set to 20 r / min, and a sputtering rate of 0.1 nm / s is used to deposit a 50-200 nm thick ITO layer on the substrate, which serves as the conductive anode for the organic light-emitting diode. After the conductive anode material ITO is deposited, the sample chamber of the magnetron sputtering coating device is filled with high-purity nitrogen gas. After atmospheric pressure is reached, the substrate is removed.

[0011] Preferably, the e-beam resist in step (3) is PMMA 950.

[0012] Preferably, in the specific procedure of step (3), first, a substrate with a conductive anode is placed on a spin coater with the surface to be spin-coated facing up, and a mechanical pump is started to firmly adsorb and fix the sample. Next, an appropriate amount of PMMA 950 solution is dropped onto the substrate with a conductive anode, and the substrate is spin-coated at 500 r / min for 5 seconds, and then at 5000 r / min for 45 to 60 seconds to form a uniform film of PMMA 950 solution on the substrate. Finally, the substrate is heated on a heating plate at 180°C for 60 seconds to fully release the anisole solvent in the PMMA 950. After the PMMA 950 is dried and hardened, a smooth surface and an electron beam resist firmly adhered to the substrate are obtained.

[0013] Preferably, in the specific procedure of step (4), the sample prepared in step (3) is first placed in the chamber of an electron microscope, with the surface to be observed and etched facing upward and fixed on the sample stage. The chamber is then evacuated using a mechanical pump and a molecular pump, and the electron beam resist is focused to allow for clear observation. Next, an electron beam exposure device matching the electron microscope is used to expose a circular array pattern of different diameters on the PMMA 950 with a precisely focused high-energy electron beam of 15 kV to 30 kV. The chamber of the electron microscope is then filled with high-purity nitrogen gas, and the sample is removed after reaching atmospheric pressure. The electron beam-exposed sample is then immersed in a dedicated developer for 45 to 60 seconds, then in isopropanol for 15 to 20 seconds, dried by blowing compressed air, and heated on a heating stage at 100°C for 30 to 60 seconds. Finally, a plasma asher is used to reduce the thickness of the electron beam resist to 40 nm to 80 nm, thereby obtaining an electron beam resist with a predetermined thickness and a blind hole structure.

[0014] Preferably, in the specific procedure of step (5), the blind hole structure sample is first placed in the chamber of the plasma cleaning machine, the mechanical pump is turned on to exhaust air to a pressure of 350 Pa, then oxygen gas is injected to make the pressure 550 Pa, the plasma cleaning machine is turned on to clean continuously for 300 seconds, and high-purity nitrogen gas is filled into the chamber of the ion cleaning machine, and the sample is taken out after the atmospheric pressure is reached.

[0015] Preferably, in the specific procedure of step (6), first, the sample obtained in step (5) is placed in the sample chamber of an evaporative coating device, with the surface to be evaporated facing downwards, and the sample is fixed on a sample tray. The hole transport layer material, the light-emitting layer and electron transport layer material, and the cathode material are placed in the evaporation sources of the evaporative coating device. Then, a mechanical pump is started to pre-evacuate the sample chamber, controlling the vacuum level in the sample chamber to 10 Pa or less. Then, a molecular pump is started to evacuate the chamber to 5×10 Pa or less. -4 The chamber is evacuated to a pressure of 100 Pa or higher, and finally, the materials on the evaporation source are heated in sequence to deposit 10 to 60 nm of hole transport layer material, 30 to 60 nm of light emitting layer material, 10 to 60 nm of electron transport layer material, and 50 to 200 nm of cathode material, where the rotation speed of the sample tray on which the substrate is placed is 20 r / min, the deposition rates of the hole transport layer material, light emitting layer material, and electron transport layer material are all 0.1 nm / s, and the deposition rate of the cathode material is 1 nm / s. After the cathode material is deposited, the sample chamber of the evaporation coating device is filled with high-purity nitrogen gas, and the sample is removed after atmospheric pressure is reached. [Effects of the Invention]

[0016] (1) The minimum pixel size of organic light-emitting diodes will be reduced to a few hundred nanometers.

[0017] (2) By introducing electron beam lithography process method, the evaporation method through fine metal mask currently used in the industry for manufacturing organic light-emitting diode display screens is abandoned, and instead of the movable fine metal mask used in the traditional method, an insulating electron beam resist is used as a fixed mask, which greatly reduces the shadow effect of evaporation coating and the errors caused by the aperture size and position accuracy of the fine metal mask, and avoids the thermal expansion and cold contraction of materials and positioning errors when moving / replacing the fine metal mask, where the above errors are all at the micron level.

[0018] (3) The complicated structure introduced in the electron beam etching process is simplified, and the advantage of the small minimum line width of the electron beam etching process is maximized. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a process flow chart of the present invention. [Figure 2] FIG. 1 is a comparative diagram of the improved electron beam lithography process of the present invention, a deposition process through a fine metal mask, and a typical electron beam lithography process. [Figure 3] 1 is a structural diagram of an organic light-emitting diode manufactured according to the present invention; [Figure 4] FIG. 1 is a diagram of a 16×15 blind hole array with 800 nm diameter on e-beam resist after 1000x magnification with the optical microscope of the present invention. [Figure 5] 1 is a view of a 6x3 blind hole array with 800 nm diameter on e-beam resist after 1900x magnification with a scanning electron microscope of the present invention. [Figure 6] 1 is a view of a 3×3 blind hole array with 800 nm diameter on an e-beam resist after 3300x magnification with a scanning electron microscope of the present invention. [Figure 7]1 is a structural diagram of a single blind hole with a diameter of 800 nm on an electron beam resist after 40,000 times magnification with a scanning electron microscope of the present invention. [Figure 8] 1 shows an atomic force microscope view of a 2×3 blind hole array with 800 nm diameter on an electron beam resist, and a thickness view of electron beam lithography. [Figure 9] FIG. 1 is a light emission diagram of an organic light emitting diode of the present invention having a diameter of 800 nm and 16×15 pixels, magnified 1000 times under an optical microscope. [Figure 10] 1 is a spectrum diagram of a spectrometer test of a 16×15 pixel organic light-emitting diode with a diameter of 800 nm according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The technical solution of the present invention will be further described below with reference to the drawings.

[0021] As shown in FIGS. 1 and 2, the electron beam etching method of the present invention for reducing the pixel size of an organic light-emitting diode to several hundred nanometers includes the following steps (1) to (6).

[0022] (1) Cleaning - Cleaning of board 6 The substrate is a transparent insulating substrate having a thickness of about 150 microns, preferably a thin glass substrate (6 in FIG. 3).

[0023] First, the substrate 6 is thoroughly washed with detergent water to remove impurities such as oil stains and dust. Next, the substrate 6 is immersed in ultrapure water, acetone, isopropanol, and ultrapure water in that order for 15 to 20 minutes each, and while immersed, the substrate is cleaned in an ultrasonic bath. Finally, the substrate 6 is dried by spraying it with compressed gas.

[0024] (2) Sputtering—Sputtering a conductive anode 5 onto a substrate 6 The conductive anode 5 uses indium tin oxide (ITO) (5 in FIG. 3).

[0025] First, a pre-cleaned substrate 6 is placed in the chamber of the magnetron sputtering coating device, with the sputtering surface of the substrate 6 facing downwards and fixed to the sample tray. The ITO target material to be sputtered is placed at the sputtering source position of the magnetron sputtering coating device. Next, a mechanical pump is started to pre-evacuate the sample chamber, controlling the vacuum level in the sample chamber to 10 Pa or less. Next, a molecular pump is started to evacuate the chamber to 1 x 10 -5 The chamber is evacuated to a pressure of at least 100 Pa. Finally, the AC sputtering source is started, the rotation speed of the sample tray on which the substrate is fixed is controlled to 20 r / min, and a 50-200 nm thick ITO film is deposited on the substrate at a sputtering rate of 0.1 nm / s, which serves as the conductive anode 5 of the organic light-emitting diode. After the conductive anode material ITO is deposited, the sample chamber of the magnetron sputtering coating device is filled with high-purity nitrogen gas, and the sample is removed after the sample chamber reaches atmospheric pressure.

[0026] (3) Spin coating: Spin coating the electron beam resist 7 onto the conductive anode 5. The electron beam resist 7 is made of PMMA 950 (7 in FIG. 3), which is an insulator, and is used as a fixed mask instead of the movable fine metal mask (1 in FIG. 3) in the deposition process through the fine metal mask.

[0027] First, use tweezers to place the ITO-sputtered substrate 6 on the spin coater, with the side to be spin-coated with photoresist facing up. Start the mechanical pump to firmly suction and fix it in place. Next, use a rubber-tipped dropper to drip an appropriate amount of PMMA 950 onto the ITO-sputtered substrate 6. Spin-coat at 500 r / min for 5 seconds, then at 5,000 r / min for 45–60 seconds to deposit a uniform film of PMMA 950 on the substrate 6. Finally, heat the substrate 6 on a heating plate at 180°C for 60 seconds to fully release the anisole solvent from the PMMA 950. After drying and hardening the PMMA 950, a fixed mask with a smooth surface and strong adhesion to the substrate 6 is obtained.

[0028] (4) Etching--etching blind hole structures in the electron beam resist 7, using electron beam lithography process to etch the required blind hole structures to separate each pixel in the electron beam resist 7 as a fixed mask.

[0029] First, the sample was placed in the chamber of a JSM-7900F scanning electron microscope with the surface to be observed and etched facing upward and fixed to the sample stage. The chamber was then evacuated using a mechanical pump and a molecular pump, and the focus was adjusted to allow clear observation of the electron beam resist 7. Next, using an electron beam exposure system compatible with the scanning electron microscope, a precisely focused high-energy electron beam of 15 kV to 30 kV was used to expose a circular array pattern of 800 nm diameter onto PMMA 950. The chamber of the JSM-7900F electron microscope was then filled with high-purity nitrogen gas, and the sample was removed after reaching atmospheric pressure. The electron beam-exposed sample was then immersed in a dedicated developer (1:3 methyl isobutyl ketone and isopropanol) for 45 to 60 s, immersed in isopropanol for 15 to 20 s, dried by blowing with compressed air, and heated on a heating stage at 100 °C for 30 to 60 s to obtain a fixed mask sample with a blind hole structure. The sample was observed under an optical microscope at 1000x magnification. Due to the magnification and diffraction limit of the optical microscope, the blind hole structures appear as black dots under the optical microscope, as shown in Figure 4. For a clearer observation, the sample with the blind hole structures was placed back into a scanning electron microscope. Images magnified at 1900x, 3300x, and 40000x are shown in Figures 5, 6, and 7. As the magnification increases, the 800 nm diameter circular hole array structure becomes increasingly clear. To characterize the height of the circular blind hole structures (the thickness of the PMMA 950), the sample with the blind hole structures was placed under an atomic force microscope and observed. The resulting image is shown in Figure 8. The height of the circular blind hole structures, approximately 140 nm to 150 nm, can be clearly seen. To make the total thickness of each organic functional layer and the conductive cathode, which will be deposited later, larger than the thickness of the fixed mask, the thickness of the fixed mask is finally reduced to 40 nm to 80 nm using a plasma asher to obtain a sample of the fixed mask with a predetermined thickness and a blind hole structure.

[0030] It can be seen from the comparison of the three methods in Figure 2 that the improved electron beam lithography process in the present invention ((1) → (2) → (3.2) → (4.2) → (5.2) → (6.2) in Figure 2) is different from the evaporation process using a fine metal mask ((1) → (2) → (3.1) → (4.1) → (5.1) in Figure 2). In the evaporation process using a fine metal mask, the gap between the fine metal mask and the substrate is large and movable, and the shadow effect, errors caused by the fine metal mask's aperture size and positioning accuracy, thermal expansion and cold contraction of the material, and positioning errors when moving or replacing the fine metal mask are all large (all in the micron level). In contrast, in the improved electron beam lithography process, the fixed mask and the substrate are in close contact with each other, which significantly reduces the shadow effect of evaporation coating, errors caused by the fine metal mask's aperture size and positioning accuracy, and avoids the thermal expansion and cold contraction of the material and positioning errors when moving or replacing the fine metal mask. This allows the pixel size of the OLED to be reduced to several hundred nanometers.

[0031] At the same time, the improved electron beam lithography process in the present invention simplifies the complicated structure introduced in the typical electron beam etching process ((1) → (2) → (3.2) → (4.2) → (5.3) → (6.3) in Figure 2), and fully utilizes the advantage of the small minimum line width of the electron beam etching process.

[0032] (5) increasing the surface work function of the conductive anode 5 on the substrate; First, a sample with a blind hole structure was placed in the chamber of the plasma cleaning machine, and the mechanical pump was turned on to exhaust air to a pressure of 350 Pa. Next, oxygen gas was injected to increase the pressure to 550 Pa, and the plasma cleaning machine was turned on to clean continuously for 300 s. The chamber of the ion cleaning machine was filled with high-purity nitrogen gas, and the sample was removed after it reached atmospheric pressure.

[0033] (6) Vapor Deposition: The hole transport layer 4, the light-emitting / electron transport layer 3, and the cathode 2 of the organic light-emitting diode are vapor-deposited on the substrate 6 to produce an organic light-emitting diode with a pixel diameter of 800 nm. The total thickness of each organic functional layer and the cathode must be greater than the thickness of the fixed mask.

[0034] First, place the sample in the sample chamber of the evaporative coating device, with the surface to be evaporated facing downwards, and fix it on the sample tray. Place the hole transport layer 4 material, the light-emitting layer / electron transport layer 3 material, and the cathode 2 material in each evaporation source of the evaporative coating device. Next, start the mechanical pump to pre-evacuate the sample chamber and control the vacuum level in the sample chamber to 10 Pa or less. Next, start the molecular pump and evacuate the chamber to 5 x 10 -4 The chamber is evacuated to a pressure of at least 100 Pa. Finally, the materials on the evaporation sources are heated in order to deposit a hole transport layer material (4 in FIG. 3) with a thickness of 10 nm to 60 nm, a light emitting layer / electron transport layer material (3 in FIG. 3) with a thickness of 30 nm to 60 nm, and a cathode material (2 in FIG. 3) with a thickness of 50 nm to 200 nm.

[0035] The rotation speed of the sample tray on which the substrate is placed is 20 r / min, the deposition rates of the hole transport layer material, light emitting layer material, and electron transport layer material are all 0.1 nm / s, and the deposition rate of the cathode material is 1 nm / s. After the conductive cathode material is deposited, the sample chamber of the evaporative coating device is filled with high-purity nitrogen gas, and the substrate is removed after reaching atmospheric pressure.

[0036] The two electrodes, the cathode and anode, of an organic light-emitting diode with a pixel diameter of 800 nm are drawn out using conductive silver paste and copper wire, and the 800 nm organic light-emitting diode is immediately tested without packaging.

[0037] 1. Luminescence test - A voltage of 10V is applied to the two electrodes, and the luminescence image of the organic light-emitting diode with a pixel diameter of 800nm ​​is magnified 1000 times by an optical microscope, as shown in Figure 9. 2. Spectral Test--The emission spectrum of the organic light-emitting diode with a pixel diameter of 800 nm was tested under Ocean Optics QE65pro spectrometer, and the spectrum diagram is shown in FIG. [Explanation of symbols]

[0038] 2, cathode 3. Light-emitting layer and electron transport layer 4. Hole transport layer 5. Conductive anode 6. Circuit board 7. Electron beam resist.

Claims

1. 1. An electron beam etching method for reducing pixel size of an organic light emitting diode, comprising: a step (1) of cleaning a substrate (6); (2) sputtering a conductive anode (5) onto a substrate (6); (3) spin-coating an electron beam resist (7) onto a conductive anode (5); Etching blind hole structures in the electron beam resist (7) (4); Increasing the surface work function of a conductive anode (5) on the substrate (5); and (6) sequentially evaporating a hole transport layer (4), a light-emitting layer and electron transport layer (3), and a cathode (2) of the organic light-emitting diode onto an electron beam resist (7) to fabricate the organic light-emitting diode.

2. 2. The electron beam etching method for reducing the pixel size of an organic light-emitting diode (OLED) according to claim 1, characterized in that, in the specific procedure of step (1), the substrate (6) is first thoroughly cleaned, then the substrate (6) is immersed in ultrapure water, acetone, isopropanol, and ultrapure water in turn for 15 to 20 minutes, and the substrate (6) is cleaned in an ultrasonic bath during the immersion, and finally the substrate (6) is dried by blowing compressed gas onto it.

3. 2. The electron beam etching method for reducing pixel size of organic light emitting diodes as claimed in claim 1, wherein the substrate (6) in step (1) is a transparent insulating substrate.

4. 2. The electron beam etching method for reducing pixel size of organic light emitting diodes as claimed in claim 1, wherein the conductive anode (5) in step (2) is indium tin oxide ITO.

5. In the specific procedure of step (2), first, the pre-cleaned substrate (6) is placed in the chamber of the magnetron sputtering coating device, the sputtering surface of the substrate (6) is placed downward and fixed on the sample tray, the ITO target material to be sputtered is placed at the sputtering source position of the magnetron sputtering coating device, then the mechanical pump is started to pre-evacuate the chamber and control the vacuum level in the sample chamber to 10 Pa or less, then the molecular pump is started to evacuate the chamber to 1×10 -5 10. The electron beam etching method for reducing the pixel size of an organic light-emitting diode (OLED) according to claim 4, further comprising: evacuating the chamber to a pressure of 100 Pa or more; finally, starting an AC sputtering source; setting the rotation speed of the sample tray on which the substrate is placed to 20 r / min; and depositing ITO to a thickness of 50 nm to 200 nm on the substrate (6) at a sputtering rate of 0.1 nm / s, which serves as the conductive anode (5) of the organic light-emitting diode; after the conductive anode material ITO is deposited, filling the sample chamber of the magnetron sputtering coating device with high-purity nitrogen gas; and removing the substrate (6) after the pressure reaches atmospheric pressure.

6. 2. The electron beam etching method for reducing pixel size of organic light emitting diodes as claimed in claim 1, wherein the electron beam resist (7) in step (3) is PMMA 950.

7. 10. The electron beam etching method for reducing the pixel size of an organic light-emitting diode (OLED) according to claim 6, wherein the specific procedure of step (3) is as follows: first, a substrate having a conductive anode (5) is placed in a spin coater with the surface to be spin-coated facing upwards, and a mechanical pump is started to firmly suction and fix the substrate; then, an appropriate amount of PMMA 950 solution is dropped onto the substrate having the conductive anode (5); the substrate is spin-coated at a rotation speed of 500 r / min for 5 seconds, and then at a rotation speed of 5,000 r / min for 45 to 60 seconds, thereby forming a uniform film of the PMMA 950 solution on the conductive anode (5); finally, the sample is heated on a heating plate at 180°C for 60 seconds, thereby sufficiently releasing the anisole solvent in the PMMA 950; after the PMMA 950 is dried and hardened, an electron beam resist (7) with a smooth surface and firmly adhering to the substrate is obtained.

8. In the specific procedure of step (4), the sample prepared in step (3) is first placed in a chamber using an electron microscope, with the surface to be observed and etched facing upward, and fixed on a sample stage. The sample is then evacuated using a mechanical pump and a molecular pump, and the focus is adjusted so that the electron beam resist (7) can be clearly observed. Next, an electron beam exposure device matching the electron microscope is used to expose the PMMA to a precisely focused high-energy electron beam of 15 kV to 30 kV. 950, then filling the chamber of the electron microscope with high-purity nitrogen gas, and removing the substrate after atmospheric pressure is reached, then immersing the substrate after electron beam exposure in a dedicated developer for 45 to 60 seconds and in isopropanol for 15 to 20 seconds, blowing it with compressed air to dry it, and heating it on a heating stage at 100°C for 30 to 60 seconds, and finally using a plasma asher to reduce the thickness of the electron beam resist (7) to 40 nm to 80 nm, thereby obtaining an electron beam resist (7) with a predetermined thickness and a blind hole structure.

9. 2. The electron beam etching method for reducing the pixel size of an organic light-emitting diode (OLED) according to claim 1, wherein the specific procedure of step (5) is as follows: first, place the sample having the blind hole structure in the chamber of a plasma cleaning machine; turn on a mechanical pump to exhaust air to a pressure of 350 Pa; then inject oxygen gas to increase the pressure to 550 Pa; turn on the plasma cleaning machine to continuously clean for 300 seconds; fill the chamber of the ion cleaning machine with high-purity nitrogen gas; and remove the sample after the pressure reaches atmospheric pressure.

10. In the specific procedure of step (6), the sample obtained in step (5) is first placed in the sample chamber of an evaporative coating device, with the surface to be evaporated facing downwards, and the sample is fixed on a sample tray. The hole transport layer (4) material, the light-emitting layer and electron transport layer (3) material, and the cathode (2) material are placed in the evaporation sources of the evaporative coating device. Next, a mechanical pump is started to pre-evacuate the sample chamber, controlling the vacuum level in the sample chamber to 10 Pa or less. Then, a molecular pump is started to evacuate the chamber to 5 × 10 Pa. -4 2. The electron beam etching method for reducing the pixel size of an organic light-emitting diode (OLED) according to claim 1, characterized in that: the chamber is evacuated to a pressure of 100 Pa or more; finally, the materials on the evaporation source are sequentially heated to sequentially deposit a hole transport layer (4) material of 10 nm to 60 nm, a light-emitting layer material of 30 nm to 60 nm, an electron transport layer material of 10 nm to 60 nm, and a cathode (2) material of 50 nm to 200 nm; after the cathode (2) material is deposited, the sample chamber of the evaporation coating device is filled with high-purity nitrogen gas; and the sample is removed after the pressure reaches atmospheric pressure.

Images