Photoetching mask and photoetching system

Abstract

The utility model provides a photoetching plate and a photoetching system. The photolithography mask comprises a substrate and a dustproof film assembly, the substrate is provided with a first substrate surface and a second substrate surface which are oppositely arranged and parallel, and a photolithography pattern layer is arranged on the first substrate surface. The dustproof film assembly comprises a dielectric layer and an outer frame, and the dielectric layer is of a transparent rigid film structure. The outer frame is provided with a first opening end and a second opening end which are opposite, and the dielectric layer seals the first opening end. The second opening end of the outer frame is attached to the first substrate face in a sealed mode, and a closed cavity is defined by the outer frame, the first substrate face and the dielectric layer. According to the technical scheme, the dielectric layer is of the rigid thin film structure and cannot deform due to air pressure change in the photoetching process, and it can be ensured that the photoetching pattern can be accurately projected to the surface of the wafer or the surface of the substrate. In addition, the photolithography mask is provided with a sealed cavity, so that the photolithography pattern is prevented from being polluted.

Description

Technical Field

[0001] This application relates to the field of semiconductor processing, and more specifically, to a photomask and a photolithography system. Background Technology

[0002] A photomask, also known as a lithography mask, is a pattern master used in photolithography processes. Its main function is to precisely replicate a pre-set photolithographic pattern onto a wafer or substrate. Typically, a photomask consists of an opaque light-blocking film forming a mask pattern structure on a transparent substrate. Its working principle is as follows: the mask pattern structure allows a light source to selectively illuminate the photoresist layer on the wafer or substrate, altering the chemical properties of the photoresist. The altered photoresist is then removed through development to obtain a patterned photoresist layer. This patterned photoresist layer can then act as a mask, facilitating subsequent processes such as selective etching, implantation, or deposition on the wafer or substrate to obtain the patterned wafer or substrate. Photomasks are widely used in fields involving photolithography processes, such as integrated circuits, flat panel displays, printed circuit boards, and microelectromechanical systems (MEMS).

[0003] In actual production, photomasks are prone to adhering to dust or other impurities, which can contaminate the photolithographic pattern and affect the subsequent pattern replication on the wafer or substrate. A common solution to this problem is to apply a dustproof film to the surface of the photomask. However, the dustproof films commonly used in existing technologies are merely flexible, transparent films, which are easily deformed or damaged, and cannot be cleaned using common methods such as high-pressure airflow, making maintenance inconvenient. Furthermore, the photolithography process generates a large amount of heat, causing the air between the dustproof film and the photomask to expand or contract under the influence of ambient temperature, leading to deformation of the dustproof film. Therefore, the outer frame of the dustproof film is usually equipped with pores to balance the internal and external air pressure, but this cannot fundamentally solve the problem of deformation of the flexible dustproof film. Moreover, the gas exchange process may introduce dust or impurities such as sulfate and ammonium ions from the environment between the dustproof film and the photomask, resulting in contamination of the photomask or dustproof film surface and negatively impacting the final photolithography effect. Utility Model Content

[0004] The purpose of this application is to provide a photomask and a photolithography system. The dielectric layer of the photomask is a rigid thin film structure, which will not deform due to changes in air pressure during the photolithography process. This ensures that the photolithographic pattern is accurately projected onto the surface of the wafer or substrate. Furthermore, a sealed cavity is provided to help ensure that the photolithographic pattern is not contaminated.

[0005] In a first aspect, this application provides a photomask, including a substrate and a dustproof film assembly. The substrate has a first substrate surface and a second substrate surface that are disposed opposite to each other and parallel to each other. A photolithographic pattern layer is disposed on the first substrate surface. The dustproof film assembly includes a dielectric layer and an outer frame. The dielectric layer is a transparent rigid thin film structure, and the outer frame has a first opening end and a second opening end that are opposite to each other. The dielectric layer seals the first opening end. The second opening end of the outer frame is sealed and adhered to the first substrate surface, and the outer frame, the first substrate surface, and the dielectric layer form a sealed cavity.

[0006] In one feasible solution, the second opening end of the outer frame is provided with a fitting part, the end face area of ​​which is larger than the end face area of ​​the second opening end.

[0007] In one feasible solution, a first auxiliary bonding structure is provided on the surface of the bonding part, and a second auxiliary bonding structure is provided on the surface of the first substrate. The first auxiliary bonding structure and the second auxiliary bonding structure cooperate to form a fixed connection between the bonding part and the surface of the first substrate.

[0008] In one feasible approach, the transmittance of the dielectric layer is greater than or equal to 99.5%.

[0009] In one feasible approach, the interior of the sealed cavity is under negative pressure.

[0010] In one feasible solution, a stepped structure is provided on the inner side of the first opening end of the outer frame, and the stepped structure is sealed and fitted with the medium layer.

[0011] In one feasible embodiment, a first sealing strip is provided on the gap at the connection between the outer frame and the first substrate surface.

[0012] In one feasible solution, a second sealing strip is provided at the gap where the outer frame connects to the medium layer.

[0013] Secondly, this application also provides a photolithography system, which includes a photomask provided in this application and a sealed photolithography chamber. The photomask is placed inside the photolithography chamber.

[0014] In one feasible scheme, the air pressure inside the sealed cavity of the photomask is P1, and the air pressure inside the photolithography chamber is P2, where P2 is greater than P1.

[0015] Compared with the prior art, the beneficial effects of this application include at least the following:

[0016] This application provides a photomask with a rigid thin-film dielectric layer. Therefore, it will not deform due to pressure changes during the photolithography process, ensuring accurate projection of the photolithographic pattern onto the wafer or substrate surface. Since the second opening of the outer frame is sealed to the first substrate surface, and the dielectric layer seals the first opening, there is no gas exchange between the sealed cavity and the external environment. Dust, sulfate, ammonium, and other impurities from the external environment cannot enter the sealed cavity, helping to ensure that the photolithographic pattern is not contaminated. Furthermore, because the dielectric layer 2 is a rigid thin-film structure, the first dielectric surface can be easily cleaned, for example, using high-pressure nitrogen cleaning, thereby greatly reducing the maintenance complexity of the photomask.

[0017] Furthermore, the sealed cavity of the photolithography plate provided in this application is under negative pressure. Therefore, during the photolithography process, the final gas pressure after the gas in the sealed cavity is increased is low, so that the pressure difference between the two sides of the dielectric layer is always at a low level. This can effectively reduce the probability of the dielectric layer being damaged or detached from the outer frame due to excessive force. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a first type of photomask according to an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of a second photomask according to an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of a third photomask according to an embodiment of this application;

[0022] Figure 4 A first schematic diagram for fabricating a dustproof membrane assembly;

[0023] Figure 5 This is a second schematic diagram of the fabrication of the dustproof membrane assembly;

[0024] Figure 6 A third schematic diagram for fabricating the dustproof membrane assembly;

[0025] Figure 7 A first schematic diagram of photomask fabrication in a negative pressure chamber;

[0026] Figure 8 A second schematic diagram showing the fabrication of a photomask in a negative pressure chamber;

[0027] Figure 9 This is a schematic diagram of a photolithography system according to an embodiment of this application.

[0028] In the figure: 1. Substrate; 2. Dielectric layer; 3. Outer frame; 4. Sealed cavity; 5. Photolithography chamber; 6. Negative pressure chamber; 7. Evacuation device; 101. First substrate surface; 102. Second substrate surface; 103. Photolithography pattern layer; 201. First dielectric surface; 202. Second dielectric surface; 203. Molten quartz glass; 204. Quartz glass layer; 301. First opening end; 302. Second opening end; 303. Adhesive part; 321. Step structure; 801. First sealing strip; 802. Second sealing strip; 901. First auxiliary adhesive structure; 902. Second auxiliary adhesive structure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0031] like Figures 1-3 As shown, this application provides a photomask, including a substrate 1 and a dustproof film assembly. The substrate 1 has a first substrate surface 101 and a second substrate surface 102 that are arranged opposite to each other and parallel to each other. A photolithographic pattern layer 103 is disposed on the first substrate surface 101. The dustproof film assembly includes a dielectric layer 2 and an outer frame 3. The dielectric layer 2 has a first dielectric surface 201 and a second dielectric surface 202 that are arranged opposite to each other and parallel to each other. The dielectric layer 2 is a transparent rigid thin film structure. The outer frame 3 has a first opening end 301 and a second opening end 302 that are opposite to each other. The dielectric layer 2 seals the first opening end 301. The second opening end 302 of the outer frame 3 is sealed and fitted to the first substrate surface 101. The outer frame 3, the first substrate surface 101, and the dielectric layer 2 form a sealed cavity 4. The first dielectric surface 201 is parallel to the first substrate surface 101 so that during the photolithography process, light can pass directly through the dielectric layer 2 without refraction, thereby ensuring accurate projection of the photolithographic pattern layer 103 onto the target position.

[0032] Since high temperatures are unavoidable during photolithography, the dielectric layer 2 can be made of high-temperature resistant transparent inorganic or polymeric materials, such as quartz glass or polyimide. Furthermore, the dielectric layer 2 should have excellent light transmittance to clearly and accurately project the photolithographic pattern onto the target location. Preferably, a material with a transmittance greater than or equal to 99.5% can be used to fabricate the dielectric layer 2. The outer frame 2 can be made of a high-temperature resistant metal material that is not easily affected by temperature expansion or contraction, such as titanium alloy. The specific materials of the dielectric layer 2 and the outer frame 2 are not strictly limited here. The photolithographic pattern layer 103 can be made of chromium or molybdenum silicide, and the photolithographic pattern is formed on the photolithographic pattern layer 103 by etching. The photolithographic pattern layer 103 can be entirely located inside the sealed cavity 4, such as... Figures 1-2 As shown; or alternatively, only the photolithographic pattern portion of the photolithographic pattern layer 103 can be located inside the sealed cavity 4, such as... Figure 3 As shown, at this time, the outer frame 3 is attached to the non-photolithographic pattern part of the photolithographic pattern layer 103, which helps to reduce the overall volume of the dustproof film assembly, avoid the dielectric layer 2 from being affected by its large area, and reduce the probability of the dielectric layer 2 being deformed or damaged.

[0033] like Figures 4-6 As shown, when fabricating the dustproof film assembly, taking the use of quartz glass to fabricate the dielectric layer 2 as an example, firstly, the first open end 301 of the outer frame 3 can be inserted into the molten quartz glass 203. After the molten quartz glass 203 solidifies to form the quartz glass layer 204, it is cut, leaving only the quartz glass within the area surrounded by the first open end 301 as the dielectric layer 2, thus completing the fabrication of the dustproof film assembly. Next, a high-temperature resistant adhesive is applied to the second open end 302 of the outer frame 3, and the outer frame 3 is attached to the first substrate surface 101. After the adhesive cures, the photomask fabrication is completed. Silicone adhesive or acrylic adhesive can be used as the adhesive; the specific type is not limited here.

[0034] During the photolithography process, the photomask generates high temperatures when exposed to light, causing an increase in air pressure within the sealed cavity 4. Since the dielectric layer 2 is a rigid thin film structure, it does not deform due to pressure changes, thus ensuring accurate projection of the photolithographic pattern onto the wafer or substrate surface. Because the second opening end 302 of the outer frame 3 is sealed to the first substrate surface 101, and the dielectric layer 2 forms a seal against the first opening end 301, there is no gas exchange between the sealed cavity 4 and the external environment. Dust, sulfate, ammonium, and other impurities from the external environment cannot enter the sealed cavity 4, helping to ensure that the photolithographic pattern layer 103 remains uncontaminated. Furthermore, after a period of use, the first dielectric surface 201 of the dielectric layer 2 may become contaminated by various impurities from the external environment. Because the dielectric layer 2 is a rigid thin film structure, the first dielectric surface 201 can be easily cleaned, for example, using high-pressure nitrogen cleaning, thereby greatly reducing the maintenance complexity of the photomask.

[0035] In one embodiment, such as Figures 1-3 As shown, a bonding portion 303 can be provided at the second opening end 302 of the outer frame 3, and the end face area of ​​the bonding portion 303 is larger than the end face area of ​​the second opening end 302. Providing the bonding portion 303 increases the bonding area between the outer frame 3 and the substrate 1, making their connection tighter and more secure. It also helps improve the airtightness between the substrate 1 and the outer frame 3, better preventing air leakage from the sealed cavity 4. Specifically, the width of the bonding portion 303 can be arbitrarily set between 5mm and 25mm; preferably, the width of the bonding portion 303 can be set to 10mm or 15mm.

[0036] In one embodiment, such as Figure 2 As shown, a first auxiliary bonding structure 901 can be provided on the surface of the bonding portion 303, and a second auxiliary bonding structure 902 can be provided on the first substrate surface 101. The first auxiliary bonding structure 901 and the second auxiliary bonding structure 902 cooperate to form a fixed connection between the bonding portion 303 and the first substrate surface 101. The first auxiliary bonding structure 901 can be a protrusion structure, and the second auxiliary bonding structure 902 can be a groove structure that cooperates with it. Alternatively, the first auxiliary bonding structure 901 can be a groove structure, and the second auxiliary bonding structure 902 can be a protrusion structure that cooperates with it. The first auxiliary bonding structure 901 and the second auxiliary bonding structure 902 help to make the connection between the substrate 1 and the outer frame 3 tighter, preventing misalignment between the substrate 1 and the outer frame 3. On the other hand, they also help to improve the airtightness between the substrate 1 and the outer frame 3, and better prevent air leakage from the sealed cavity 4.

[0037] In one embodiment, the sealed cavity 4 is under negative pressure. For example... Figures 7-8As shown, during the fabrication of the photomask, the substrate 1 and the dustproof film assembly are first placed in the negative pressure chamber 6. Then, the air is evacuated using the vacuum device 7 to stabilize the air pressure inside the negative pressure chamber 6 at 0.507 bar (i.e., 0.5 standard atmospheres). Next, the first open end 201 coated with adhesive is pressed onto the first substrate surface 301 of the substrate 1, and the pressed state is maintained for a preset time (e.g., 30 seconds or 1 minute) to allow the adhesive to cure, thus completing the bonding of the substrate 1 and the dustproof film assembly. Because the photomask fabrication process is completed in a negative pressure environment, and after fabrication, there is no gas exchange between the sealed cavity 4 and the external environment, the sealed cavity 4 is always under negative pressure, and its air pressure value is the same as the internal air pressure value of the negative pressure chamber 6. During photolithography, the gas inside the sealed cavity 4 absorbs heat and expands under light irradiation, thereby increasing the air pressure. Since the gas inside the sealed cavity 4 is under negative pressure at room temperature, the final gas pressure of the gas inside the sealed cavity 4 after pressurization is lower than that of the gas at normal pressure. Therefore, the pressure difference between the two sides of the medium layer 2 is always at a low level, that is, the pressure that the medium layer 2 needs to withstand is small. This can effectively reduce the probability that the medium layer 2 will be damaged or detached from the outer frame 3 due to excessive force.

[0038] In one embodiment, such as Figures 2-3 As shown, a stepped structure 321 can be provided on the inner side of the first opening end 301 of the outer frame 3, and the stepped structure 321 is sealed and fitted with the dielectric layer 2. The stepped structure 321 helps to increase the contact area between the dielectric layer 2 and the first opening end 301, making the bonding between the dielectric layer 2 and the first opening end 301 tighter and reducing the probability of the dielectric layer 2 detaching from the outer frame 3. In addition, the stepped structure 321 can also be replaced by a multi-level stepped structure or a groove structure (not shown in the figure), thereby further increasing the contact area between the dielectric layer 2 and the first opening end 301. The specific structure is not limited here.

[0039] In one embodiment, such as Figures 2-3 As shown, a first sealing strip 801 can be provided at the gap where the fitting part 303 of the outer frame 3 connects to the first substrate surface 101. Furthermore, a second sealing strip 802 can be provided at the gap where the outer frame 3 connects to the dielectric layer 2. The first sealing strip 801 and the second sealing strip 802 can be made of high-temperature resistant sealing materials, such as polyurethane, neoprene rubber, or silicone rubber. Providing the first sealing strip 801 and the second sealing strip 802 helps ensure the airtightness of the sealed cavity 4, preventing various impurities from the external environment from entering the sealed cavity 4 and contaminating the photolithographic pattern layer 103.

[0040] like Figure 9As shown, this application also provides a photolithography system, including the aforementioned photomask and a sealed photolithography chamber 5, with the photomask placed inside the photolithography chamber 5. The gas pressure inside the sealed cavity 4 is P1, and the gas pressure inside the photolithography chamber 5 is P2, where P2 is greater than P1. During the photolithography process, the gas inside the sealed cavity 4 absorbs heat and expands under light irradiation, causing the gas pressure to rise from P1 to P11. By reasonably setting the numerical relationship between P2 and P1, after the pressure increase, P11 > P2, and the pressure difference across the dielectric layer 2 is (P11 - P2). However, if the gas pressure inside the sealed cavity 4 and the gas pressure inside the photolithography chamber 5 are both P2, during the photolithography process, the gas pressure inside the sealed cavity 4 rises to P3, and the pressure difference across the dielectric layer 2 is (P3 - P2). Obviously, (P3-P2)>(P11-P2), therefore, in the photolithography system of this application, the dielectric layer 2 needs to withstand less pressure, which can effectively reduce the probability of the dielectric layer 2 being damaged or detached from the outer frame 3 due to excessive force.

[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photomask, characterized in that, include: The substrate (1) has a first substrate surface (101) and a second substrate surface (102) that are arranged opposite to each other and parallel to each other. A photolithographic pattern layer (103) is provided on the first substrate surface (101). The dustproof film assembly includes a dielectric layer (2) and an outer frame (3). The dielectric layer (2) is a transparent rigid film structure. The outer frame (3) has a first opening end (301) and a second opening end (302) opposite to each other. The dielectric layer (2) forms a seal on the first opening end (301). The second opening end (302) of the outer frame (3) is sealed and attached to the first substrate surface (101). The outer frame (3), the first substrate surface (101) and the dielectric layer (2) form a closed cavity (4).

2. The photomask according to claim 1, characterized in that, The second opening end (302) of the outer frame (3) is provided with a fitting part (303), and the end face area of ​​the fitting part (303) is greater than the end face area of ​​the second opening end (302).

3. The photomask according to claim 2, characterized in that, The bonding part (303) is provided with a first auxiliary bonding structure (901) on its surface, and a second auxiliary bonding structure (902) is provided on the first substrate surface (101). The first auxiliary bonding structure (901) and the second auxiliary bonding structure (902) cooperate to form a fixed connection between the bonding part (303) and the first substrate surface (101).

4. The photomask according to claim 1, characterized in that, The transmittance of the dielectric layer (2) is greater than or equal to 99.5%.

5. The photomask according to claim 1, characterized in that, The sealed cavity (4) is under negative pressure.

6. The photomask according to claim 1, characterized in that, A stepped structure (321) is provided on the inner side of the first opening end (301) of the outer frame (3), and the stepped structure (321) is sealed and fitted with the medium layer (2).

7. The photomask according to claim 2, characterized in that, A first sealing strip (801) is provided on the gap at the connection between the fitting part (303) of the outer frame (3) and the first substrate surface (101).

8. The photomask according to claim 1, characterized in that, A second sealing strip (802) is provided on the gap at the connection between the outer frame (3) and the medium layer (2).

9. A photolithography system, characterized in that, The device includes a photomask as described in any one of claims 1-8, and further includes a sealed photolithography chamber (5), wherein the photomask is placed inside the photolithography chamber (5).

10. The photolithography system according to claim 9, characterized in that, The air pressure inside the sealed cavity (4) of the photomask is P1, and the air pressure inside the photolithography chamber (5) is P2, wherein P2 is greater than P1.

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