Micro OLED anode structure preparation method capable of improving light emitting intensity

Abstract

The invention relates to manufacturing of a Micro OLED (Organic Light Emitting Diode), in particular to a preparation method of a Micro OLED anode structure for improving light emitting intensity, which comprises the following steps of: sequentially preparing a SiO2 film layer and a SiN film layer on a substrate, and spin-coating a first photoresist layer on the surface of the SiN film layer; preparing an anode reflection bowl structure based on different etching rates of the SiO2 film layer and the SiN film layer; preparing a metal film layer on the surface of the anode reflection bowl structure, spin-coating a second photoresist layer on the surface of the metal film layer, and removing the second photoresist layer on the two sides and the metal film layer on the two sides; preparing ITO film layers on the surfaces of the second photoresist layer in the middle and the SiN film layers on the two sides, spin-coating third photoresist layers on the surfaces of the ITO film layers, removing the third photoresist layers on the two sides, and removing the third photoresist layer in the middle and the ITO film layers on the two sides; according to the technical scheme provided by the invention, the defect that the light emitting intensity of the Micro OLED is difficult to improve through light condensation can be overcome.

Description

Technical Field

[0001] The present invention relates to the manufacture of Micro OLEDs, and specifically to a method for preparing a Micro OLED anode structure that improves the light extraction intensity. Background Art

[0002] Micro OLED is an advanced display technology, widely used in high-resolution and small-size display devices, especially in the AR / VR and wearable device markets with broad prospects.

[0003] The light-emitting principle of Micro OLED is based on the electroluminescence phenomenon of organic materials, and light emission is achieved through carrier injection, transport, recombination, and exciton radiative decay. One of the main reasons for the low display brightness of OLED products is that the light emitted by the light-emitting layer is scattered outward, resulting in a decrease in the light extraction intensity. Therefore, when facing the problem that the emitted light is scattered and cannot be focused, leading to a low light extraction intensity, how to fabricate a new anode structure to solve the problem of light scattering and improve the light extraction intensity has become an urgent technical problem in this field. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] In view of the above-mentioned drawbacks of the prior art, the present invention provides a method for preparing a Micro OLED anode structure that improves the light extraction intensity, which can effectively overcome the defect that it is difficult to improve the light extraction intensity of Micro OLEDs by focusing in the prior art.

[0006] (II) Technical Solutions

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A method for preparing a Micro OLED anode structure that improves the light extraction intensity, comprising the following steps:

[0009] S1. Sequentially prepare a SiO2 film layer and a SiN film layer on a substrate, and spin-coat a first photoresist layer on the surface of the SiN film layer;

[0010] S2. Prepare an anode reflection bowl structure based on the different etching rates of the SiO2 film layer and the SiN film layer;

[0011] S3. Prepare a metal film layer on the surface of the anode reflection bowl structure, spin-coat a second photoresist layer on the surface of the metal film layer, and remove the second photoresist layer and the metal film layer on both sides;

[0012] S4. Prepare an ITO film layer on the surfaces of the middle second photoresist layer and the SiN film layers on both sides. Spin-coat a third photoresist layer on the surface of the ITO film layer, remove the third photoresist layers on both sides, and then remove the third photoresist layer in the middle and the ITO film layers on both sides to obtain a reflective bowl-shaped Micro OLED anode structure.

[0013] Preferably, in S1, preparing a SiO2 film layer and a SiN film layer on the substrate in sequence and spin-coating a first photoresist layer on the surface of the SiN film layer includes:

[0014] Adopt the CVD process to prepare a SiO2 film layer and a SiN film layer on the substrate in sequence and spin-coat a first photoresist layer on the surface of the SiN film layer;

[0015] Among them, the thicknesses of both the SiO2 film layer and the SiN film layer are 0.5 - 2 μm.

[0016] Preferably, in S2, based on the different etching rates of the SiO2 film layer and the SiN film layer, preparing the anode reflective bowl structure includes:

[0017] S21. Adopt the photolithography and development process to remove the first photoresist layer in the middle;

[0018] S22. Adopt the dry etching process. While removing the first photoresist layers on both sides, the SiO2 film layer and the SiN film layer start to etch downwards. Based on the different etching rates of the SiO2 film layer and the SiN film layer, form the anode reflective bowl structure.

[0019] Preferably, in S22, when adopting the dry etching process to remove the first photoresist layers on both sides, the SiO2 film layer and the SiN film layer start to etch downwards. Based on the different etching rates of the SiO2 film layer and the SiN film layer, forming the anode reflective bowl structure includes:

[0020] Since the etching rate of the SiN film layer is greater than that of the SiO2 film layer, during the etching process, the etching length of the SiN film layer is greater than that of the SiO2 film layer, and the isotropic etching of the dry etching process has no direction selectivity. During the downward etching process, the already etched part above gradually undergoes lateral etching. By controlling the lateral etching rate, the anode reflective bowl structure is gradually formed.

[0021] Preferably, in S3, preparing a metal film layer on the surface of the anode reflective bowl structure, spin-coating a second photoresist layer on the surface of the metal film layer, and removing the second photoresist layers on both sides and the metal film layers on both sides includes:

[0022] S31. Adopt the evaporation or PVD process to prepare a metal film layer on the surface of the anode reflective bowl structure and spin-coat a second photoresist layer on the surface of the metal film layer;

[0023] S32. Remove the second photoresist layers on both sides using a photolithography and development process;

[0024] S33. Remove the metal film layers on both sides using an etching process;

[0025] Among them, the metal film layer is an Al film layer or an Ag film layer. The thickness of the Al film layer is 20 - 200 μm, and the thickness of the Ag film layer is 10 - 200 μm.

[0026] Preferably, in S4, an ITO film layer is prepared on the surfaces of the second photoresist layer in the middle and the SiN film layers on both sides. A third photoresist layer is spin-coated on the surface of the ITO film layer, and the third photoresist layers on both sides are removed. Then, the third photoresist layer in the middle and the ITO film layers on both sides are removed to obtain a reflective bowl-shaped Micro OLED anode structure, including:

[0027] S41. Deposit ITO in one step on the surfaces of the second photoresist layer in the middle and the SiN film layers on both sides to form an ITO film layer, and spin-coat a third photoresist layer on the surface of the ITO film layer;

[0028] S42. Remove the third photoresist layers on both sides using a photolithography and development process;

[0029] S43. Remove the third photoresist layer in the middle and the ITO film layers on both sides using an etching process to obtain a reflective bowl-shaped Micro OLED anode structure;

[0030] Among them, the thickness of the ITO film layer is 10 - 200 nm.

[0031] (III) Beneficial Effects

[0032] Compared with the prior art, the method for preparing a Micro OLED anode structure for improving light extraction intensity provided by the present invention can minimize the loss of light during the reflection process through the reflective bowl-shaped structure design. At the same time, through the metal film layer, the light emitted by the ITO film layer can be reflected and coincide with the light emitted in the forward direction, effectively improving the light extraction intensity through light concentration, thereby being able to improve the display brightness of the Micro OLED. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a flowchart of the present invention;

[0035] Figure 2 Schematic diagram of sequentially preparing a SiO2 film layer, a SiN film layer, and spin-coating a first photoresist layer on a substrate in the present invention;

[0036] Figure 3 Schematic diagram of the anode reflection bowl structure in the present invention;

[0037] Figure 4 Schematic diagram of preparing a metal film layer on the surface of the anode reflection bowl structure in the present invention;

[0038] Figure 5 Schematic diagram of removing the second photoresist layer on both sides and the metal film layer on both sides in the present invention;

[0039] Figure 6 Schematic diagram of preparing an ITO film layer on the surface of the second photoresist layer in the middle and the SiN film layer on both sides in the present invention;

[0040] Figure 7 Schematic diagram of removing the third photoresist layer on both sides, and then removing the third photoresist layer in the middle and the ITO film layer on both sides in the present invention;

[0041] Figure 8 Schematic diagram of the structure of the Micro OLED anode structure in the present invention. Detailed implementation manners

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] Method for preparing a Micro OLED anode structure for improving light extraction intensity, as Figure 1 shown, S1, sequentially prepare a SiO2 film layer 2 and a SiN film layer 3 on a substrate 1, and spin-coat a first photoresist layer 4 on the surface of the SiN film layer 3, specifically including:

[0044] Adopt the CVD process to sequentially prepare a SiO2 film layer 2 and a SiN film layer 3 on the substrate 1, and spin-coat a first photoresist layer 4 on the surface of the SiN film layer 3 (as Figure 2 shown);

[0045] Among them, the thicknesses of both the SiO2 film layer 2 and the SiN film layer 3 are 0.5 - 2 μm.

[0046] S2. Based on the different etching rates of the SiO2 film layer 2 and the SiN film layer 3, an anode reflective bowl structure 5 is prepared, specifically including:

[0047] S21. Use photolithography and development processes to remove the middle first photoresist layer 4;

[0048] S22. Use dry etching process to start etching the SiO2 film layer 2 and the SiN film layer 3 downward while removing the first photoresist layer 4 on both sides. Based on the different etching rates of the SiO2 film layer 2 and the SiN film layer 3, an anode reflective bowl structure 5 is formed (as Figure 3 shown).

[0049] Specifically, in S22, when using the dry etching process to remove the first photoresist layer 4 on both sides, the SiO2 film layer 2 and the SiN film layer 3 start to be etched downward. Based on the different etching rates of the SiO2 film layer 2 and the SiN film layer 3, an anode reflective bowl structure 5 is formed, including:

[0050] Since the etching rate of the SiN film layer 3 is greater than that of the SiO2 film layer 2, during the etching process, the etching length of the SiN film layer 3 is greater than that of the SiO2 film layer 2, and the isotropic etching of the dry etching process has no direction selectivity. During the downward etching process, the already etched part above gradually undergoes lateral etching. By controlling the lateral etching rate, an anode reflective bowl structure 5 is gradually formed.

[0051] S3. Prepare a metal film layer 6 on the surface of the anode reflective bowl structure 5, spin-coat a second photoresist layer on the surface of the metal film layer 6, and remove the second photoresist layer and the metal film layer 6 on both sides, specifically including:

[0052] S31. Use evaporation or PVD process to prepare a metal film layer 6 on the surface of the anode reflective bowl structure 5 (as Figure 4 shown), and spin-coat a second photoresist layer on the surface of the metal film layer 6;

[0053] S32. Use photolithography and development processes to remove the second photoresist layer on both sides;

[0054] S33. Use etching process to remove the metal film layer 6 on both sides (as Figure 5 shown);

[0055] Among them, the metal film layer 6 is an Al film layer or an Ag film layer. The thickness of the Al film layer is 20 - 200 μm, and the thickness of the Ag film layer is 10 - 200 μm.

[0056] S4. Prepare an ITO film layer 8 on the surface of the second photoresist layer in the middle and the SiN film layers 3 on both sides. Spin-coat a third photoresist layer on the surface of the ITO film layer 8, and remove the third photoresist layers on both sides. Then remove the third photoresist layer in the middle and the ITO film layers 8 on both sides to obtain a reflective bowl-shaped Micro OLED anode structure, which specifically includes:

[0057] S41. Deposit ITO on the surface of the second photoresist layer in the middle and the SiN film layers 3 on both sides at one time to form an ITO film layer 8 (as Figure 6 shown), and spin-coat a third photoresist layer on the surface of the ITO film layer 8;

[0058] S42. Remove the third photoresist layers on both sides by means of photolithography and development;

[0059] S43. Remove the third photoresist layer in the middle and the ITO film layers 8 on both sides by means of etching (as Figure 7 shown) to obtain a reflective bowl-shaped Micro OLED anode structure (as Figure 8 shown);

[0060] Among them, the thickness of the ITO film layer 8 is 10 - 200 nm.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Preparation method of Micro OLED anode structure for improving light extraction intensity, characterized in that: It includes the following steps: S1. Sequentially prepare an SiO2 film layer (2) and a SiN film layer (3) on a substrate substrate (1), and spin-coat a first photoresist layer (4) on the surface of the SiN film layer (3); S2. Prepare an anode reflective bowl structure (5) based on the different etching rates of the SiO2 film layer (2) and the SiN film layer (3); S3. Prepare a metal film layer (6) on the surface of the anode reflective bowl structure (5), spin-coat a second photoresist layer on the surface of the metal film layer (6), and remove the second photoresist layers on both sides and the metal film layers (6) on both sides; S4. Prepare an ITO film layer (8) on the surface of the middle second photoresist layer and the SiN film layers (3) on both sides, spin-coat a third photoresist layer on the surface of the ITO film layer (8), remove the third photoresist layers on both sides, and then remove the third photoresist layer in the middle and the ITO film layers (8) on both sides to obtain a reflective bowl-shaped Micro OLED anode structure.

2. The method for preparing a Micro OLED anode structure for improving light extraction intensity according to claim 1, characterized in that: In S1, sequentially preparing an SiO2 film layer (2) and a SiN film layer (3) on a substrate substrate (1), and spin-coating a first photoresist layer (4) on the surface of the SiN film layer (3) includes: Adopt a CVD process to sequentially prepare an SiO2 film layer (2) and a SiN film layer (3) on a substrate substrate (1), and spin-coat a first photoresist layer (4) on the surface of the SiN film layer (3); Among them, the thicknesses of both the SiO2 film layer (2) and the SiN film layer (3) are 0.5 - 2 μm.

3. The method for preparing the Micro OLED anode structure for improving the light extraction intensity according to claim 1, characterized in that: In S2, preparing an anode reflective bowl structure (5) based on the different etching rates of the SiO2 film layer (2) and the SiN film layer (3) includes: S21. Adopt a photolithography and development process to remove the first photoresist layer (4) in the middle; S22. While removing the first photoresist layers (4) on both sides by a dry etching process, the SiO2 film layer (2) and the SiN film layer (3) start to be etched downward. Based on the different etching rates of the SiO2 film layer (2) and the SiN film layer (3), an anode reflective bowl structure (5) is formed.

4. The method for preparing a Micro OLED anode structure for improving light extraction intensity according to claim 3, wherein: In S22, while removing the first photoresist layers (4) on both sides by a dry etching process, the SiO2 film layer (2) and the SiN film layer (3) start to be etched downward. Based on the different etching rates of the SiO2 film layer (2) and the SiN film layer (3), an anode reflective bowl structure (5) is formed, including: Since the etching rate of the SiN film layer (3) is greater than that of the SiO2 film layer (2), during the etching process, the etching length of the SiN film layer (3) is greater than that of the SiO2 film layer (2), and the isotropic etching of the dry etching process has no direction selectivity. During the downward etching process, the etched part above gradually undergoes lateral etching. By controlling the lateral etching rate, an anode reflective bowl structure (5) is gradually formed.

5. The method for preparing a Micro OLED anode structure for improving light extraction intensity according to claim 1, characterized in that: In S3, preparing a metal film layer (6) on the surface of the anode reflective bowl structure (5), spin-coating a second photoresist layer on the surface of the metal film layer (6), and removing the second photoresist layers on both sides and the metal film layers (6) on both sides includes: S31. Prepare a metal film layer (6) on the surface of the anode reflective bowl structure (5) by evaporation coating or PVD process, and spin-coat a second photoresist layer on the surface of the metal film layer (6); S32. Remove the second photoresist layers on both sides by photolithography and development process; S33. Remove the metal film layers (6) on both sides by etching process; Among them, the metal film layer (6) is an Al film layer or an Ag film layer. The thickness of the Al film layer is 20 - 200 μm, and the thickness of the Ag film layer is 10 - 200 μm.

6. The method for preparing a Micro OLED anode structure for improving light extraction intensity according to claim 1, characterized in that: In S4, an ITO film layer (8) is prepared on the surface of the middle second photoresist layer and the SiN film layers (3) on both sides. A third photoresist layer is spin-coated on the surface of the ITO film layer (8), and the third photoresist layers on both sides are removed. Then, the middle third photoresist layer and the ITO film layers (8) on both sides are removed to obtain a reflective bowl-shaped Micro OLED anode structure, including: S41. Deposit ITO film in one step on the surface of the middle second photoresist layer and the SiN film layers (3) on both sides to form an ITO film layer (8), and spin-coat a third photoresist layer on the surface of the ITO film layer (8); S42. Remove the third photoresist layers on both sides by photolithography and development process; S43. Remove the middle third photoresist layer and the ITO film layers (8) on both sides by etching process to obtain a reflective bowl-shaped Micro OLED anode structure; Among them, the thickness of the ITO film layer (8) is 10 - 200 nm.

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