Photoetching mask and strong microcavity structure forming process adopting same

Abstract

The invention relates to a semiconductor technology, in particular to a photoetching mask and a strong microcavity structure forming technology adopting the photoetching mask, the photoetching mask comprises a photoetching mask body, and a developing open area is arranged on the photoetching mask body; each developing open area comprises a red light open area, a green light open area and a blue light open area; light transmitting layers are arranged in the red light open area, the green light open area and the blue light open area; the light transmittances of the light transmitting layers in the red light open area, the green light open area and the blue light open area are different; by controlling the light transmittance of the corresponding area of the photoetching mask, the exposure degrees in different PR areas during exposure are different, so that the developing rates are different, and the etching technology is matched to realize that different areas of the strong microcavity structure have different groove depths; the forming of the groove in the strong micro-cavity structure can be realized through one-time photoetching and etching, so that the cost and the process flow are greatly saved.

Description

Technical Field

[0001] The invention relates to a semiconductor process, in particular to a photolithography mask and a strong microcavity structure forming process using the photolithography mask. Background Art

[0002] Compared with traditional displays, Micro OLED uses a single-crystal silicon chip as a driving backplane on which to manufacture OLED display devices, eliminating the external DDIC and effectively increasing the display area of ​​the micro display.

[0003] As a rising star in the display industry, Micro OLED has the advantages of light weight, small size and high resolution, and is widely used in the fields of augmented reality (AR) and virtual reality (VR).

[0004] In order to improve the luminous efficiency of Micro OLED, a strong microcavity structure is often used.

[0005] To achieve strong microcavities, trenches of different depths need to be etched and then filled with SIO.

[0006] The traditional process is to form this structure through three times of photolithography + etching. This process is complex and has high requirements for the overlay during photolithography of each pixel.

[0007] With the continuous development of semiconductor manufacturing technology, photolithography plays a vital role in the manufacture of micro-nano structures.

[0008] As a key tool in the photolithography process, the design and manufacture of photolithography masks directly affect the accuracy and quality of photolithography patterns.

[0009] Traditional photolithography masks usually adopt a single transmittance design, which makes it difficult to meet the requirements of different exposure levels in different areas in the manufacture of complex micro-nano structures.

[0010] This results in the need for multiple photolithography and etching processes when manufacturing complex structures such as strong microcavity structures, which increases manufacturing costs and process complexity.

[0011] At the same time, in the manufacturing process of strong microcavity structures, the control of the development rate of the protective layer and the accuracy of the etching process are also key factors.

[0012] The existing etching process has difficulty in controlling the etching depth in different areas, and it is difficult to complete the groove forming by one photolithography + etching.

[0013] The existing patent CN111584357A - A deep trench etching method does not clearly disclose the technical content for solving the above technical problems.

[0014] Therefore, in order to improve or solve at least one of the above problems, it is necessary to improve the existing equipment or process for forming a strong microcavity structure. Summary of the invention

[0015] The object of the present invention is to provide a photolithography mask structure which can realize different developing rates in different regions of a multi-layer composite thin film structure.

[0016] In order to achieve the above object, the technical solution adopted by the present invention is:

[0017] A photolithography mask comprises a photolithography mask body, on which a development opening area is provided;

[0018] Each of the development open areas includes a red light open area, a green light open area and a blue light open area;

[0019] A light-transmitting layer is arranged in the red light open area, the green light open area and the blue light open area; and the light transmittances of the light-transmitting layers in the red light open area, the green light open area and the blue light open area are different.

[0020] The light transmittance of the light-transmitting layer in the red light open area is greater than the light transmittance of the light-transmitting layer in the green light open area; the light transmittance of the light-transmitting layer in the green light open area is greater than the light transmittance of the light-transmitting layer in the blue light open area.

[0021] A molding process for manufacturing a strong microcavity structure, the molding process uses the photolithography mask; the development rate of the protective layer is controlled by the photolithography mask.

[0022] The molding process comprises the following steps:

[0023] Step 1: On the driving backplane, a Ti layer, a TiN layer, an Al layer and a protective layer are sequentially deposited using physical vapor deposition and chemical vapor deposition;

[0024] Step 2: Photolithography and developing the protective layer using a photolithography mask;

[0025] Step 3: Etching the protective layer and / or the Al layer by an etching process;

[0026] Step 4: After step 3 is completed, the grooves of different depths in the strong micro-cavity structure are formed. If a new groove of a strong micro-cavity structure needs to be formed, repeat steps 1-3.

[0027] The etching process comprises the following steps:

[0028] S1: Preliminary etching; using a hard template; using etching gas to perform preliminary etching of the protective layer;

[0029] S2: mixed etching; using a hard template and etching gas, the grooves in the R area, G area and B area of ​​the strong microcavity structure are gradually etched.

[0030] The protective layer includes a SIO layer and a SIN layer; in the step 1, a Ti layer, a TiN layer, an Al layer, a SIO layer and a SIN layer are sequentially deposited on the driving backplane by using physical vapor deposition and chemical vapor deposition.

[0031] The S1 requires that after etching, the etching of the R region in the strong microcavity structure stops at the Al layer, the etching of the G region stops at the SIO layer, and the etching of the B region stops at the SIN layer.

[0032] The etching gas in S1 is F-based gas; the etching gas in S2 is F-based gas and Cl-based gas; Cl-based gas is used when etching the Al layer; and F-based gas is used when etching the protective layer.

[0033] In said S2, multiple etchings are required to achieve the etching and forming of the grooves in the R region, the G region and the B region;

[0034] The etching sequence is as follows:

[0035] First etching: using Cl-based gas as the main etching gas, first etch the Al layer in the R area until the Al layer in the R area is etched to the set position;

[0036] Second etching: Replace the etching gas, use F-based gas as the main etching gas, and etch the SIO layer in the G area to the Al layer;

[0037] The third etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area and the G area; until the Al layer in the R area and the G area is etched to the set position;

[0038] Fourth etching: replace the etching gas with F-based gas as the main etching gas; etch the SIO layer in area B to the Al layer;

[0039] The fifth etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area, G area and B area; until the Al layer in the R area, G area and B area is etched to the set position; obtaining the groove depth in the R area, G area and B area.

[0040] After step 4 is completed, the protective layer needs to be removed. Before removing the protective layer, a protective material is required to be filled in the corresponding groove of the Al layer. Then, dry etching is used to remove the protective layer. After the protective layer is removed, O-based gas is used to remove the protective material.

[0041] The advantages of the present invention are:

[0042] The invention discloses a photolithography mask and a strong microcavity structure forming process using the photolithography mask.

[0043] The present invention controls the transmittance of the corresponding area of ​​the photolithography mask to achieve different exposure degrees in different areas of the PR during exposure; thereby, the development rates are different, and the etching technology is used to achieve different groove depths in different areas of the strong microcavity structure. The formation of the grooves in the strong microcavity structure can be achieved through one-time photolithography + etching, which greatly saves costs and process flows, and the formed grooves can also gather light that deviates from the vertical angle, enhance the light intensity and reduce light string. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The following is a brief description of the contents expressed in each of the drawings in the specification of the present invention:

[0045] Figure 1 The multilayer composite film structure formed in step 1 of the present invention;

[0046] Figure 2 is a schematic diagram of a local structure of a photolithography mask in the present invention;

[0047] Figure 3 for Figure 1 Development results after different degrees of exposure;

[0048] Figure 4 This is a schematic diagram of the structure of S1 after etching of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure of S2 after etching of the present invention;

[0050] Figure 6 It is a schematic diagram of the structure after the groove is filled with protective material in the present invention;

[0051] Figure 7 This is a schematic diagram of the structure after the SIN layer / SIO layer is removed in the present invention;

[0052] Figure 8 It is a structural schematic diagram of the OLED strong microcavity structure in the present invention. DETAILED DESCRIPTION

[0053] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0054] A photolithography mask comprises a photolithography mask body, on which a development open area is arranged; each of the development open areas comprises a red light open area, a green light open area and a blue light open area; a light-transmitting layer is arranged in the red light open area, the green light open area and the blue light open area; the light-transmitting layers in the red light open area, the green light open area and the blue light open area have different light transmittances; the present invention realizes precise exposure control of different areas through the above-mentioned design by using materials with different light transmittances; the photolithography mask is a key tool for defining patterns in the photolithography process.

[0055] It usually consists of a transparent substrate (such as quartz glass) and an opaque pattern layer (such as chrome); of course, it can also be made of other materials as needed.

[0056] In the present invention, the photolithography mask body is provided with development open areas, which are used to control the exposure degree of different areas during the photolithography process; the development open areas are the parts of the photolithography mask that allow light to pass through, and are used to define the areas that need to be exposed.

[0057] Each open area is provided with a light-transmitting layer, and the transmittance of these light-transmitting layers is different; the light-transmitting layer in the red light open area (R area) has the highest transmittance, the light-transmitting layer in the green light open area (G area) has the second lowest transmittance, and the light-transmitting layer in the blue light open area (B area) has the lowest transmittance; the purpose of this design is to achieve different development rates in different areas during the development process by controlling the degree of exposure, thereby forming grooves of different depths in the subsequent etching process.

[0058] The present invention can accurately control the exposure degree of different areas through materials with different light transmittances, thereby achieving different development rates in different areas; this design provides a basis for the subsequent etching process, and cooperates with the subsequent etching process to achieve different groove depths in different areas of the strong microcavity structure.

[0059] Traditional photolithography processes usually require multiple photolithography passes to form complex trench structures.

[0060] The present invention realizes exposure control of different areas through a single photolithography step, greatly simplifies the process flow and reduces costs; the photolithography mask disclosed in the present invention can reduce the production efficiency of different areas of a strong microcavity structure having different groove depths; reduces process steps, shortens the manufacturing cycle, and improves production efficiency.

[0061] The formed groove Al layer morphology can gather light that deviates from the vertical angle, enhance the light intensity and reduce light string, thereby improving the optical performance.

[0062] Furthermore, in the present invention, the transmittance of the light-transmitting layer in the red light open area is greater than the transmittance of the light-transmitting layer in the green light open area; the transmittance of the light-transmitting layer in the green light open area is greater than the transmittance of the light-transmitting layer in the blue light open area; through this design, different development rates in different areas can be achieved in one photolithography process, thereby forming grooves of different depths in the subsequent etching process.

[0063] A molding process for manufacturing a strong microcavity structure, the molding process uses the photolithography mask; the development rate of the protective layer is controlled by the photolithography mask; the present invention is based on the design of the photolithography mask, and the present invention relates to a process using a specifically designed photolithography mask to achieve precise etching of different areas by controlling the development rate of the protective layer; this method can complete a complex structure that originally requires multiple photolithography + etching to achieve in one photolithography + etching, which greatly simplifies the process flow and reduces costs.

[0064] Further, the molding process described in the present invention comprises the following steps:

[0065] Step 1: On the driving backplane, a Ti layer, a TiN layer, an Al layer and a protective layer are sequentially deposited using physical vapor deposition and chemical vapor deposition;

[0066] Step 2: Photolithography and developing the protective layer using a photolithography mask;

[0067] Step 3: Etching the protective layer and / or the Al layer by an etching process;

[0068] Step 4: After step 3 is completed, the grooves of different depths in the strong micro-cavity structure are formed. If a new groove of a strong micro-cavity structure needs to be formed, repeat steps 1-3.

[0069] In the present invention, step 1: thin film deposition;

[0070] Operation: On the driver backplane, the following thin films are deposited using physical vapor deposition (PVD) and chemical vapor deposition (CVD) techniques in sequence:

[0071] Ti layer: used to provide good adhesion and conductivity.

[0072] TiN layer: acts as a barrier layer to prevent diffusion between the Al layer and the Ti layer.

[0073] Al layer: as the main conductive layer, used to form a microcavity structure.

[0074] Protective layer: usually includes SiO layer and SiN layer, which is used to protect the Al layer and serve as isolation protection in subsequent etching.

[0075] Through multi-layer thin film deposition, a basic structure is provided for subsequent lithography and etching processes.

[0076] Step 2: photolithography and development;

[0077] Operation: Use the designed photolithography mask to photolithographically develop the protective layer.

[0078] The photolithography mask has light-transmitting layers with different light transmittances in the red light (R area), green light (G area) and blue light (B area) open areas, respectively, so that the exposure degree and development rate are different in different areas.

[0079] Red light open area (R area): the highest transmittance and the fastest development rate.

[0080] Green light open zone (G zone): The transmittance is second highest and the development rate is moderate.

[0081] Blue light open area (area B): the lowest transmittance and the slowest development rate.

[0082] Purpose: By controlling the exposure degree of different areas, different development rates can be achieved in different areas, providing precise pattern definition for subsequent etching processes.

[0083] Step 3: Etching process

[0084] Operation: Etching of the protection layer and / or the Al layer is achieved through an etching process.

[0085] Finally, groove forming of a strong microcavity structure is achieved.

[0086] Step 4: Groove forming is completed;

[0087] Operation: After step 3 is completed, the grooves of different depths in the strong micro-cavity structure are formed. If a new groove of a strong micro-cavity structure is required, repeat steps 1-3 above.

[0088] Purpose: To complete the fabrication of a strong microcavity structure and ensure that the groove depths in different areas meet the design requirements; by repeating the above steps, multiple strong microcavity structures can be fabricated to meet different application requirements.

[0089] Furthermore, the etching process in the present invention comprises the following steps:

[0090] S1: Preliminary etching; using a hard template; using etching gas to perform preliminary etching of the protective layer;

[0091] S2: mixed etching; using a hard template and etching gas, the grooves in the R area, G area and B area of ​​the strong microcavity structure are gradually etched.

[0092] S1 of the present invention: preliminary etching;

[0093] Etching gas selection:

[0094] F-based gas (such as CF4, SF6, etc.) is used as the etching gas for the preliminary etching.

[0095] F-based gases have high etching selectivity and etching rate, and are suitable for etching materials such as SiO and SiN.

[0096] Etching process:

[0097] Perform preliminary etching on the protective layer, and the etching depth and stop position are controlled according to the design requirements:

[0098] R zone: etching stops at the Al layer; G zone: etching stops at the SiO layer; B zone: etching stops at the SiN layer.

[0099] Purpose: Through preliminary etching, the initial etching depth of different areas is formed to provide a basis for subsequent mixed etching.

[0100] And S2: mixed etching; through mixed etching, trench etching in different areas is gradually achieved, and finally trenches of different depths are obtained.

[0101] Etching gas selection: Use F-based gas and Cl-based gas (such as Cl2, BCl3, etc.) to gradually realize the groove etching of R area, G area and B area in the strong microcavity structure.

[0102] Cl-based gas has a higher Al layer etching rate and is suitable for etching the Al layer.

[0103] Furthermore, the protective layer in the present invention includes a SIO layer and a SIN layer; in the step 1, it is required to sequentially deposit a Ti layer, a TiN layer, an Al layer, a SIO layer and a SIN layer on the driving backplane using physical vapor deposition and chemical vapor deposition; the protective layer of the present invention adopts the design of the SIO layer and the SIN layer; the protective layer can be used for signal monitoring: the SiO layer and the SiN layer will generate specific signals during the etching process, and these signals can be captured by the monitoring equipment; by monitoring these signals, the etching parameters (such as etching gas flow, etching time, etching power, etc.) can be adjusted in real time to ensure the accuracy and consistency of etching; by controlling the feedback etching signal, the etching error can be reduced and the repeatability and stability of etching can be improved.

[0104] Furthermore, in S1 described in the present invention, after etching, the etching of the R region in the strong microcavity structure stops at the Al layer, the etching of the G region stops at the SIO layer, and the etching of the B region stops at the SIN layer; based on this design, after photolithography and development, different stop layer requirements of the R, G, and B regions after etching are achieved; this stop layer design can cooperate with subsequent etching processes to achieve the formation of grooves of different depths; this differentiated photolithography and development result based on the etching stop layer design provides a basis for the subsequent formation of the microcavity structure.

[0105] Furthermore, in the present invention, the etching gas in S1 adopts F-based gas; the etching gas in S2 adopts F-based gas and Cl-based gas; Cl-based gas is used when etching the Al layer; F-based gas is used when etching the protective layer; F-based gas: Etching object: F-based gas (such as CF4, SF6, etc.) is mainly used to etch silicon dioxide (SiO2) and silicon nitride (Si3N4); F-based gas generates fluorine radicals (F) in a plasma state, which react with SiO2 to generate volatile SiF4, thereby achieving etching.

[0106] In step S1, F-based gas is used to etch the R region, the G region, and the B region, stopping at the Al layer, the SiO layer, and the SiN layer, respectively.

[0107] Cl-based gas: Cl-based gas (such as Cl2, BCl3) is mainly used to etch metal (such as Al layer); Cl2 reacts with Al layer to generate volatile AlCl3, thereby achieving efficient etching. BCl3 is used to reduce the oxide layer on the surface of Al layer and promote the etching process.

[0108] Application in the present invention: In step S2, Cl-based gas is used to etch the Al layer, ensuring that the Al layers in the R region, the G region and the B region are accurately etched.

[0109] The protective layer (such as SiO2 or Si3N4) is usually etched using F-based gases; the F-based gases react with the protective layer material to generate volatile by-products, thereby achieving etching; when etching the protective layer, F-based gases are used to ensure the accuracy and selectivity of etching.

[0110] F-based gases have high selectivity for SiO2 and Si3N4 and can precisely control the etching depth; Cl-based gases have a high etching rate for the Al layer, and the resulting Al layer Cl3 is easy to volatilize, ensuring an efficient etching process; by reasonably selecting gases and process parameters, anisotropic etching can be achieved, ensuring that the etched structure has good sidewall quality and depth control.

[0111] Furthermore, in S2 of the present invention, multiple etchings are required to achieve the etching and forming of the grooves in the R region, the G region and the B region;

[0112] The etching sequence is as follows:

[0113] First etching: using Cl-based gas as the main etching gas, first etch the Al layer in the R area until the Al layer in the R area is etched to the set position;

[0114] Second etching: Replace the etching gas, use F-based gas as the main etching gas, and etch the SIO layer in the G area to the Al layer;

[0115] The third etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area and the G area; until the Al layer in the R area and the G area is etched to the set position;

[0116] Fourth etching: replace the etching gas with F-based gas as the main etching gas; etch the SIO layer in area B to the Al layer;

[0117] The fifth etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area, G area and B area; until the Al layer in the R area, G area and B area is etched to the set position; obtaining the groove depth in the R area, G area and B area.

[0118] Mixed etching. In the mixed etching stage, the groove etching of the R area, G area and B area is gradually realized through multiple etchings.

[0119] The specific etching sequence is as follows: first etching;

[0120] Etching gas: Cl-based gas (such as Cl2, BCl3) is the main etching gas.

[0121] Etching target: Etch the Al layer in the R region until the set position of the Al layer in the R region is reached.

[0122] Purpose: To form the initial groove depth of the R zone;

[0123] Second etching;

[0124] Etching gas: Change to F-based gas (such as SF6, CF4).

[0125] Etching target: Etch the SiO layer in the G area until it reaches the Al layer.

[0126] Purpose: To expose the Al layer in the G region, so as to facilitate the subsequent etching of the Al layer in the G region by Cl-based gas;

[0127] The third etching;

[0128] Etching gas: Cl-based gas is the main etching gas.

[0129] Etching target: Etch the Al layer in the R area and the G area until the set position of the Al layer in the R area and the G area is reached.

[0130] Purpose: To further deepen the groove depth in R and G zones to ensure that the design requirements are met.

[0131] The fourth etching;

[0132] Etching gas: Change to F-based gas.

[0133] Etching target: Etch the SiO layer in area B until the Al layer is etched.

[0134] Purpose: To expose the Al layer in area B, so as to facilitate the subsequent etching of the Al layer in area G by Cl-based gas.

[0135] The fifth etching;

[0136] Etching gas: Cl-based gas is the main etching gas.

[0137] Etching target: Etch the Al layer of the R area, the G area, and the B area until the Al layer of the R area, the G area, and the B area is etched to the set position.

[0138] Purpose: To ultimately form the groove depths of the R, G, and B regions, ensuring that the groove depths of each region meet the design requirements.

[0139] Furthermore, after step 4 described in the present invention is completed, the protective layer needs to be removed; before removing the protective layer, it is required to fill the corresponding groove of the Al layer with protective material; then dry etching is used to remove the protective layer; after the protective layer is removed, O-based gas is used to remove the protective material; after step 4 is completed, the protective layer removal process is performed, and the protective material is filled in the Al layer groove; before removing the protective layer, it is required to fill the corresponding groove of the Al layer with protective material to prevent damage to the Al layer during the subsequent protective layer removal process.

[0140] Commonly used protective materials include photoresist (PR) or other materials with excellent filling ability.

[0141] Dry etching to remove the protective layer

[0142] After filling the protective material: After filling the Al layer trench with the protective material, the protective layer (such as the SiO layer and the SiN layer) is removed using a dry etching technique.

[0143] Dry etching is usually carried out in a plasma reactor, where a high-frequency power supply is used to excite plasma in a low-pressure gas, and the high-energy particles in the plasma are used to remove materials through chemical reactions or physical bombardment.

[0144] Etching gas selection: For the removal of the SiN layer, hot phosphoric acid (H3PO4) can be used for wet etching; for the removal of the SiO layer, it is recommended to use F-based gases (such as CF4, SF6) for dry etching to avoid damage to the Al layer film by DHF (hydrofluoric acid).

[0145] After the protective layer is removed: After the protective layer (SiO layer and SiN layer) is completely removed, plasma treatment is performed using an O-based gas (such as O2) to remove the protective material filled in the Al layer groove.

[0146] Plasma treatment: By adjusting the time and power of plasma treatment, the process can be optimized to ensure that the protective material is completely removed while avoiding damage to the Al layer.

[0147] By filling the Al layer trench with protective material, the Al layer can be effectively protected from etching damage, thereby ensuring the accuracy of etching.

[0148] Reduced damage risk: Using O-based gas to remove protective materials avoids possible damage to the Al layer caused by using DHF, improving the stability and reliability of the structure. Specific embodiment:

[0150] 1. On the driver backplane, use PVD+CVD technology to deposit TI layer / TIN layer / Al layer / SIO layer / SIN layer thin films, such as Figure 1 As shown;

[0151] 2. Design the photo mask and use materials with different light transmittance in the R / G / B open areas to achieve different exposure levels in different areas during exposure, so that the development rates are different. Finally, the following is obtained: Figure 3 The development results;

[0152] 3. Use SIN and SIO as hardmask, F-based gas as main etching gas, R region etching stops at Al layer, G region etching stops at SIO, B region etching stops at SIN, such as Figure 4 As shown;

[0153] 4. Assume that the depth of each groove of R / G / B is H1 / H2 / H3, and use Cl-based gas as the main etching gas. First, etch the Al layer in the R region, and stop etching the Al layer when etching to (H1-H2); then etch the SIO in the G region to the Al layer, and then etch the Al layer to (H1-H3) in the R region, and then stop etching aluminum in the G region (H2-H3); then etch the B region to the Al layer, and then etch the Al layer in the three regions together, and finally obtain the depth of each groove of R / G / B to be H1 / H2 / H3, as shown in FIG. Figure 5 As shown;

[0154] 5. Here, three grooves of different depths have been formed, which can be used to supplement the subsequent SIN layer / SIO layer removal process; in order to prevent the Al layer from being damaged when removing the SIN layer / SIO layer, a layer of PR or other materials with excellent filling ability can be spin-coated, and then directional dry etching can be used to obtain the following Figure 6 As shown;

[0155] 6. The SIN layer can be removed by hot phosphoric acid wet etching, but the SIO layer is recommended to be dry etched with F-based gas to avoid DHF damage to the Al layer film. After the SIN layer and SIO layer are removed, PR is removed with O-based gas. The results are as follows: Figure 7 As shown; the final strong microcavity structure can be obtained as shown in Figure 8 .

[0156] The present invention adopts a novel photolithography technology; a photo mask is designed, and materials with different light transmittances are used in each open area of ​​R / G / B, so that different exposure degrees of different areas can be achieved during exposure, thereby different development rates are achieved, and etching technology is used to achieve different groove depths in different areas, so that a structure that requires three photolithography + etching to form can be formed by one photolithography + etching, which greatly saves costs and process flow, and the groove Al layer morphology formed can also gather light that deviates from the vertical angle, enhance light intensity and reduce light string.

[0157] The present invention uses photoresist to transfer patterns. By designing the mask, different light-transmitting materials are used for each light-transmitting area of ​​R, G, and B, wherein the extinction coefficient of the R area is the smallest, the extinction coefficient of the B area is the largest, and the G area is in the middle. After exposure and development, the development depths of different areas are different, thereby realizing one-time etching to form multi-depth grooves.

[0158] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A photolithography mask, characterized in that: It includes a photolithography mask body, on which a development open area is provided; Each of the development open areas includes a red light open area, a green light open area and a blue light open area; A light-transmitting layer is arranged in the red light open area, the green light open area and the blue light open area; and the light transmittances of the light-transmitting layers in the red light open area, the green light open area and the blue light open area are different.

2. A photolithography mask according to claim 1, characterized in that: The light transmittance of the light-transmitting layer in the red light open area is greater than the light transmittance of the light-transmitting layer in the green light open area; the light transmittance of the light-transmitting layer in the green light open area is greater than the light transmittance of the light-transmitting layer in the blue light open area.

3. A molding process for manufacturing a strong microcavity structure, characterized in that: The molding process uses the photolithography mask as described in any one of claims 1-2; The development rate of the protective layer is controlled by a photolithographic mask.

4. A molding process for manufacturing a strong microcavity structure according to claim 2, characterized in that: The molding process comprises the following steps: Step 1: On the driving backplane, a Ti layer, a TiN layer, an Al layer and a protective layer are sequentially deposited using physical vapor deposition and chemical vapor deposition; Step 2: Photolithography and developing the protective layer using a photolithography mask; Step 3: Etching the protective layer and / or the Al layer by an etching process; Step 4: After step 3 is completed, the grooves of different depths in the strong micro-cavity structure are formed. If a new groove of a strong micro-cavity structure needs to be formed, repeat steps 1-3.

5. A molding process for manufacturing a strong microcavity structure according to claim 4, characterized in that: The etching process comprises the following steps: S1: preliminary etching; using a hard template; using etching gas to perform preliminary etching of the protective layer; S2: mixed etching; using a hard template and etching gas to gradually achieve groove etching in the R area, G area and B area of ​​the strong microcavity structure.

6. A molding process for manufacturing a strong microcavity structure according to claim 5, characterized in that: The protective layer includes a SIO layer and a SIN layer; in the step 1, a Ti layer, a TiN layer, an Al layer, a SIO layer and a SIN layer are sequentially deposited on the driving backplane by using physical vapor deposition and chemical vapor deposition.

7. A molding process for manufacturing a strong microcavity structure according to claim 6, characterized in that: The S1 requires that after etching, the etching of the R region in the strong microcavity structure stops at the Al layer, the etching of the G region stops at the SIO layer, and the etching of the B region stops at the SIN layer.

8. A molding process for manufacturing a strong microcavity structure according to claim 5, characterized in that: The etching gas in S1 is F-based gas; the etching gas in S2 is F-based gas and Cl-based gas; Cl-based gas is used when etching the Al layer; and F-based gas is used when etching the protective layer.

9. A molding process for manufacturing a strong microcavity structure according to claim 8, characterized in that: In said S2, multiple etchings are required to achieve the etching and forming of the grooves in the R region, the G region and the B region; The etching sequence is as follows: First etching: using Cl-based gas as the main etching gas, first etch the Al layer in the R area until the Al layer in the R area is etched to the set position; Second etching; Replace the etching gas, use F-based gas as the main etching gas, and etch the SIO layer in the G area to the Al layer; The third etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area and the G area; Until the Al layer in the R region and the G region is etched to the set position; Fourth etching: replace the etching gas with F-based gas as the main etching gas; etch the SIO layer in area B to the Al layer; The fifth etching: using Cl-based gas as the main etching gas, and then etching the Al layer in the R area, G area and B area; until the Al layer in the R area, G area and B area is etched to the set position; obtaining the groove depth in the R area, G area and B area.

10. A molding process for manufacturing a strong microcavity structure according to claim 4, characterized in that: After step 4 is completed, the protective layer needs to be removed. Before removing the protective layer, a protective material is required to be filled in the corresponding groove of the Al layer. Then, the protective layer is removed by dry etching. After the protective layer is removed, an O-based gas is used to remove the protective material.

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