An objective lens anti-pollution device

Abstract

The application discloses an objective lens anti-pollution device and belongs to the field of photoetching technology. The objective lens anti-pollution device comprises: a gas inlet body, an inside of the gas inlet body is provided with a gas inlet flow channel, a bottom surface of the gas inlet body is provided with a containing groove, and the gas inlet flow channel is arranged at the outer periphery of the containing groove; a baffle body is arranged in the containing groove, and the top surface of the baffle body is arranged in a spaced mode with the groove bottom of the containing groove; the top surface of the baffle body is provided with a first gas outlet flow channel, a second gas outlet flow channel with a wide top and a narrow bottom is formed in the center of the baffle body, the first gas outlet flow channel is arranged around the outer periphery of the second gas outlet flow channel, and the first gas outlet flow channel is in communication with the gas inlet flow channel. The application can form a stable and uniform air curtain protection layer in the device, and has a better anti-pollution effect.

Description

Technical Field

[0001] The present invention relates to the technical field of photolithography, and in particular to an anti-pollution device for an objective lens. Background Art

[0002] During the exposure process of the photolithography machine, the organic solvent in the photoresist on the surface of the silicon wafer will evaporate due to heat and adhere to the lens of the objective lens, affecting the exposure effect and resulting in a low product yield.

[0003] In existing technology, a protective film is often installed on the objective lens to prevent organic contamination. However, this film is expensive, has a short lifespan, and requires frequent replacement, which is a cumbersome process. Alternatively, a method of blowing air from one side and extracting air from the other is used to form an air curtain between the lens and the silicon wafer to isolate contaminants from the lens. However, this method places high demands on the integrity, flatness, and uniformity of the air curtain layer. Furthermore, the flow field near the objective lens is complex, and this often fails to fully isolate contaminants from the lens, resulting in poor anti-contamination effectiveness. Summary of the Invention

[0004] The object of the present invention is to provide an objective lens anti-pollution device, which can form a stable and uniform air curtain protection layer inside the device and achieve better anti-pollution effect.

[0005] To achieve the above objectives, the following technical solutions are provided:

[0006] An objective lens anti-pollution device, comprising:

[0007] An air intake body, wherein an air intake passage is provided inside the air intake body, a receiving groove is provided on the bottom surface of the air intake body, and the air intake passage is provided on the periphery of the receiving groove;

[0008] The baffle body is placed in the accommodating groove, and the top surface of the baffle body is spaced apart from the bottom of the accommodating groove; the top surface of the baffle body is provided with a first outlet air flow channel, and the center of the baffle body is passed through to form a second outlet air flow channel that is wider at the top and narrower at the bottom, the first outlet air flow channel is arranged around the outer periphery of the second outlet air flow channel, and is connected to the inlet air flow channel.

[0009] Optionally, the second outlet flow channel is a frustum structure.

[0010] Optionally, the inlet air duct is connected to the bottom of the first outlet air duct; the first outlet air duct is in a wedge-shaped structure that is narrow at the top and wide at the bottom.

[0011] Optionally, a circle of first air vents is provided on the side wall of the inlet air duct close to the first outlet air duct, and a circle of second air vents is provided on the side wall of the first outlet air duct close to the inlet air duct. The number of the first air vents corresponds one-to-one to the number of the second air vents, and the first air vents are connected to the corresponding second air vents.

[0012] Optionally, the baffle body has a first position and a second position that are centrally symmetrical in circumference, and a third position located between the first position and the second position, and the first position is the air intake position; in the direction from the first position to the third position, the aperture of the second air vent gradually decreases, and / or the hole depth of the second air vent gradually becomes longer; in the direction from the third position to the second position, the aperture of the second air vent gradually increases, and / or the hole depth of the second air vent gradually decreases.

[0013] Optionally, a buffer flow channel is further provided between the outer peripheral surface of the baffle body and the circumferential groove wall of the accommodating groove, and the buffer flow channel is communicated with the first vent hole and the second vent hole at the same time.

[0014] Optionally, a third vent hole is provided on a circumferential side wall of the second outlet flow channel, and the third vent hole horizontally connects the first outlet flow channel and the second outlet flow channel.

[0015] Optionally, a circle of fourth ventilation holes is provided on the bottom surface of the baffle body, and the fourth ventilation holes are connected to the first outlet flow channel.

[0016] Optionally, a light-transmitting portion is formed at the center of the air inlet body, and the light from the objective lens is transmitted to the workpiece to be photoetched via the light-transmitting portion and the second air outlet channel in sequence.

[0017] Optionally, the light-transmitting portion includes a first light-transmitting through hole opened on the air inlet body, and the first light-transmitting through hole is connected to the accommodating groove; the first light-transmitting through hole can be selectively sealed with a light-transmitting member.

[0018] Optionally, the objective lens anti-pollution device further comprises a light shielding plate, which is provided at the bottom of the baffle body and is used to partially shield a hollow area in the center of the baffle body to form a target exposure field of view.

[0019] Optionally, a circle of limiting bosses is circumferentially provided on the bottom of the baffle body, and the air inlet body abuts against the limiting bosses to limit the placement depth of the baffle body in the accommodating groove.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The air flow first enters the containing groove at the top of the baffle body from bottom to top through the air inlet channel and the first air outlet channel, which makes the air flow buffered and homogenized, and achieves the purpose of stable flow; since the first air outlet channel is arranged around the second air outlet channel, with the continuous input of the gas and the flow guiding effect of the second air outlet channel which is wide at the top and narrow at the bottom, the air flow on the circumference of the second air outlet channel converges to the center of the baffle body at the same time, and finally escapes from top to bottom to realize air outlet, thereby forming a complete and stable air curtain protection layer, and the pollutants cannot diffuse to the objective lens direction and are blocked by the air curtain protection layer, thereby realizing effective isolation of the to-be-photolithographed member and the objective lens. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Fig. 1 is a structural schematic diagram of an objective lens anti-pollution device in an embodiment of the present application;

[0023] Figure 2 Fig. 2 is a bottom view of the objective lens anti-pollution device in the embodiment of the present application;

[0024] Figure 3 Fig. 3 is a front view of the objective lens anti-pollution device in the embodiment of the present application;

[0025] Figure 4 Fig. 4 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application;

[0026] Figure 5 Fig. 5 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application; Figure 4

[0027] Fig. 6 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application; Figure 6

[0028] Fig. 7 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application; Figure 7

[0029] Fig. 8 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application; Figure 8 Figure 3 Fig. 9 is a sectional view of the objective lens anti-pollution device in the embodiment of the present application;

[0030] Reference signs:

[0031] 10, air inlet body; 20, baffle body; 30, light shield plate;

[0032] 11, air inlet channel; 12, containing groove; 13, first air hole; 14, air inlet; 15, mounting boss; 16, light-transmitting piece;

[0033] 21, first air outlet channel; 22, second air outlet channel; 23, buffer flow channel; 24, second air hole; 25, limiting boss. DETAILED DESCRIPTION

[0034] ​To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0037] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0041] Example 1

[0042] like Figure 1-8 As shown, this embodiment provides an objective lens anti-pollution device that can be installed on the objective lens to prevent pollutants volatilized from the photoetched workpiece from diffusing onto the lens of the objective lens; the objective lens anti-pollution device includes an air inlet body 10. Figure 4-6 The air intake body 10 is provided with an air intake passage 11 inside, and a downwardly open receiving groove 12 is provided on the bottom surface of the air intake body 10. The air intake passage 11 is arranged around the outer periphery of the receiving groove 12. Figure 4 、 5 7, the objective lens anti-contamination device also includes a baffle body 20 in an annular structure. The baffle body 20 is placed in the receiving groove 12, and the top surface of the baffle body 20 is spaced apart from the bottom of the receiving groove 12. A first outlet flow channel 21 is formed on the top surface of the baffle body 20. A second outlet flow channel 22, which is wider at the top and narrower at the bottom, is formed through the center of the baffle body 20. The first outlet flow channel 21 is arranged around the outer periphery of the second outlet flow channel 22 and is connected to the inlet flow channel 11. Gas passes through the inlet flow channel 11, the first outlet flow channel 21, the receiving groove 12, and the second outlet flow channel 22 in sequence, and then escapes from the bottom of the baffle body 20, forming an air curtain protective layer between the objective lens and the workpiece to be photoetched.

[0043] In the objective lens anti-pollution device provided in this embodiment, the airflow first enters the receiving groove 12 at the top of the baffle body 20 from bottom to top through the inlet flow channel 11 and the first outlet flow channel 21. This process allows the airflow to be buffered and homogenized, achieving the purpose of stable flow. Since the first outlet flow channel 21 is arranged around the second outlet flow channel 22, with the continuous input of gas, coupled with the guiding effect of the second outlet flow channel 22, which is wide at the top and narrow at the bottom, the airflow in the circumferential direction of the second outlet flow channel 22 is simultaneously gathered toward the center of the baffle body 20, and finally escapes from top to bottom to achieve gas discharge, thereby forming a complete and stable air curtain protective layer. The pollutants are blocked by the air curtain protective layer and cannot diffuse into the interior of the device (i.e., the objective lens direction), thereby achieving effective isolation between the photoetched part and the objective lens. Optionally, the second outlet flow channel 22 is a truncated cone structure; that is, any horizontal cross-section of the second outlet flow channel 22 is circular, so that the airflow is more consistent when it converges at various points in the circumferential direction, and the formation of the air curtain protective layer is also more stable and uniform. The air curtain in the prior art can only be formed by unilateral air outlet and air extraction on the opposite side of the air outlet. Therefore, the air curtain has poor stability. If the air flow is slightly too large or there is external interference, it is easy to cause air field turbulence, destroying the integrity of the air curtain and easily causing local contamination of the objective lens. In this embodiment, the air curtain protective layer is formed by uniformly delivering the airflow to an upper area for stabilization, and then directing the airflow toward the center and downward. The airflow is distributed within a 360-degree circumferential range, ensuring the stability, integrity and uniformity of the entire air curtain protective layer, and achieving a better anti-fouling effect. In specific implementation, the objective lens anti-pollution device can be installed on the lens holder of the objective lens to fit the objective lens as closely as possible, ensuring that the lens can be fully isolated from contaminants by the air curtain protective layer.

[0044] Optionally, the inlet flow channel 11 is annular; specifically, it can be a circular ring; refer to Figure 1 The air inlet 14 is provided on the outer peripheral surface of the air inlet body 10, and the air inlet channel 11 is connected to the air inlet 14, and the outside air is fed into the air inlet channel 11 through the air inlet 14. For the annular air inlet channel 11, generally one air inlet 14 is provided. Further optionally, the receiving groove 12 is a circular groove; Figure 4 and Figure 5 The outer circumferential surface of the baffle body 20 and the circumferential wall of the receiving groove 12 form a seal to prevent gas from leaking through this area, preventing it from properly flowing to the first outlet flow channel 21 and affecting the proper formation of the air curtain protective layer. Optionally, the air inlet body 10 has a circular structure to facilitate the arrangement of the air inlet flow channel 11 and the receiving groove 12, and also to facilitate assembly with the objective lens. Furthermore, the central axes of the air inlet body 10, the air inlet flow channel 11, and the baffle body 20 coincide with each other.

[0045] The inlet channel 11 is connected to the bottom of the first outlet channel 21, so that the airflow enters from the bottom of the first outlet channel 21 and is buffered and homogenized in the first outlet channel 21 before it diffuses upward, which is beneficial to improve the stability of the airflow. Figure 5 The first outlet air channel 21 is a wedge-shaped structure that is narrow at the top and wide at the bottom, which can further extend the buffering time of the airflow in the first outlet air channel 21 and is more conducive to the uniform operation of the airflow. Figure 4-7 A circle of first air holes 13 is provided on the side wall of the inlet flow channel 11 close to the first outlet flow channel 21, and a circle of second air holes 24 is provided on the side wall of the first outlet flow channel 21 close to the inlet flow channel 11. The number of the first air holes 13 corresponds to the number of the second air holes 24 one by one. The first air holes 13 are connected to the corresponding second air holes 24, thereby realizing the connection between the inlet flow channel 11 and the first outlet flow channel 21.

[0046] Since there is only one air inlet 14, after the gas enters the intake channel 11 through the air inlet 14, the gas output in the circumferential direction of the intake channel 11 is not uniform, that is, the gas output of the second air vent 24 is also uneven along the circumference. The gas output is the smallest at a position symmetrically distributed with respect to the air inlet 14, and the gas output is the largest at a position arranged at a 90-degree angle with respect to the air inlet 14. Figure 7 and Figure 8 In this embodiment, the circumference of the baffle body 20 has a first position P1 and a second position P2 that are centrally symmetrical, and a third position P3 located between the first position P1 and the second position P2. The air inlet 14 and the first position P1 are located in the same radial direction, that is, the first position P1 is the air inlet position for the baffle body 20; in the direction from the first position P1 to the third position P3, the aperture of the second air hole 24 gradually decreases, or the hole depth of the second air hole 24 gradually becomes longer, or the aperture of the second air hole 24 gradually decreases while the hole depth gradually increases; in the direction from the third position P3 to the second position P3, the aperture of the second air hole 24 gradually increases, or the hole depth of the second air hole 24 gradually decreases, or the aperture of the second air hole 24 gradually increases while the hole depth gradually decreases. Since the larger the aperture and the smaller the hole depth, the greater the gas output, and the smaller the aperture and the longer the hole depth, the less gas output, the above arrangement makes it possible for the gas to be discharged from the second vent 24. The gas output at the position which is set at a 90-degree angle to the air inlet 14 is reduced, while the gas output at the position which is centrally symmetrical with the air inlet 14 is increased, thereby balancing the gas output in different areas and achieving uniform gas output as much as possible, which helps to improve the homogenization of the air flow, the uniformity and stability of the air curtain isolation layer.

[0047] Since the second air hole 24 needs to pass through the side wall of the first air outlet flow channel 21 near the air inlet flow channel 11, in order to adapt to the setting of the second air hole 24 with different hole depths, the first air outlet flow channel 21 near the air inlet flow channel 11 is provided with a first air hole 13 and a second air hole 24. Figure 8 It can be seen that the wall thickness of the side wall of the first air outlet flow channel 21 near the air inlet flow channel 11 is uneven, and the wall thickness of the side wall of the first air outlet flow channel 21 far from the air inlet flow channel 11 is also uneven, and is complementary to the wall thickness of the side wall near the air inlet flow channel 11. This setting is to ensure that the width of the first air outlet flow channel 21 in the circumferential direction is consistent, and to ensure that the cross section of the second air outlet flow channel 22 is a regular circle, thereby making the distribution of the airflow in the circumferential direction more uniform.

[0048] Referring to Figure 5 , a buffer flow channel 23 is further arranged between the outer circumferential surface of the baffle body 20 and the circumferential groove wall of the accommodating groove 12. The buffer flow channel 23 is in communication with the first air hole 13 and the second air hole 24 at the same time, and the gas in the air inlet flow channel 11 enters the first air outlet flow channel 21 in sequence through the first air hole 13, the buffer flow channel 23 and the second air hole 24. Since the air inlet 14 is generally arranged only in the circumferential direction of the air inlet body 10, after the airflow is input from the air inlet 14, most of it will first enter the first air outlet flow channel 21 near the air inlet 14, and the farther away from the air inlet 14, the smaller the air flow in the corresponding first air outlet flow channel 21, which is easy to cause uneven distribution of the airflow in the circumferential direction, affecting the uniformity and stability of the air curtain protection layer. Therefore, a buffer flow channel 23 is arranged between the baffle body 20 and the air inlet body 10, which can further buffer and homogenize the airflow from the air inlet flow channel 11, so that the airflow is distributed more uniformly in the circumferential direction, which is helpful for the stable formation of the air curtain protection layer. Optionally, the outer circumferential surface of the baffle body 20 is recessed inward to form a wedge-shaped space between the baffle body 20 and the air inlet body 10, which is narrow at the top and wide at the bottom. The wedge-shaped space can be used as the buffer flow channel 23, and the structure of being narrow at the top and wide at the bottom is used to adapt to the structure of the first air outlet flow channel 21, so as to ensure that the airflow is fully stabilized and homogenized at the bottom before entering the bottom of the second air outlet flow channel 22. When the buffer flow channel 23 is formed, the part of the outer circumferential surface of the baffle body 20 which does not form the buffer flow channel 23 should still be in sealing cooperation with the air inlet body 10, that is, the wedge-shaped space is only formed by part of the outer circumferential surface of the baffle body 20.

[0049] Furthermore, third vent holes are provided on the circumferential sidewalls of the second outlet flow channel 22. These third vent holes horizontally connect the first outlet flow channel 21 and the second outlet flow channel 22, allowing airflow to flow directly out of the first outlet flow channel 21 along the radial direction of the baffle body 20. This increases the radial velocity component of the air curtain protective layer, enhancing its stability and improving its ability to block contaminants. Similarly, a circle of fourth vent holes is provided on the bottom surface of the baffle body 20. The fourth vent holes are connected to the first outlet flow channel 21, allowing airflow to flow directly out of the first outlet flow channel 21 through the fourth vent holes. This creates a further gas protective layer at the bottom of the baffle body 20, which cooperates with the aforementioned air curtain protective layer to further prevent contaminants from diffusing toward the objective lens.

[0050] In a specific implementation, a light-transmitting portion is formed in the center of the air inlet body 10, and the light from the objective lens is sequentially transmitted through the light-transmitting portion and the second outlet flow channel 22 to the workpiece to be photoetched, ensuring the normal progress of the exposure process. Further, the light-transmitting portion includes a first light-transmitting through hole opened in the center of the air inlet body 10; optionally, refer to Figure 4 The light-transmitting portion further includes a light-transmitting member 16, which closes the first light-transmitting through hole, ensuring normal light transmission while playing the role of isolating pollutants with a physical structure, thereby improving the anti-fouling effect. In this embodiment, the light-transmitting member 16 can be a protective film. Under the action of the aforementioned air curtain protective layer, very few pollutants can escape to the protective film, so the service life of the protective film can be greatly extended and the replacement frequency can be significantly reduced. Optionally, a mounting boss 15 is provided on the top surface of the air inlet body 10, and the first light-transmitting through hole passes through the mounting boss 15 and is connected to the receiving groove 12. The protective film is provided in the first air-permeable through hole of the mounting boss 15. The above-mentioned arrangement can avoid interference between the protective film and the baffle body 20, thereby ensuring that there is sufficient gas buffer space above the baffle body 20.

[0051] Optionally, refer to Figure 5 and Figure 7 The baffle body 20 is circumferentially provided with a circle of limiting bosses 25 at its bottom. When the baffle body 20 is placed in the receiving groove 12 for assembly, the intake body 10 abuts against the limiting bosses 25 to limit the placement depth of the baffle body 20 in the receiving groove 12, ensuring sufficient gas buffer space above the baffle body 20. Optionally, the baffle body 20 and the intake body 10 are connected by a bolt structure.

[0052] refer to Figure 2 、 48. The objective lens anti-contamination device also includes a light shielding plate 30, which is disposed at the bottom of the baffle body 20 and is used to form a target exposure field of view. In specific implementations, the exposure field of view projected onto the workpiece to be photoetched should be rectangular. However, to ensure uniform formation of the air curtain protective layer, the cross-sectional shape of the second outlet airflow channel 22 is circular. Light passing through the entire objective lens anti-contamination device forms a circular field of view. Therefore, a light shielding plate 30 is required. A second light-transmitting through hole of the same shape as the target field of view is disposed at the center of the light shielding plate 30. When the light shielding plate 30 is mounted on the baffle body 20, it partially blocks the hollow area at the center of the baffle body 20, allowing light from the objective lens to only pass through the second light-transmitting through hole in the light shielding plate 30, thereby forming the target exposure field of view on the workpiece to be photoetched. Furthermore, while the light shielding plate 30 blocks the baffle body 20, it also reduces the air outlet area at the bottom of the baffle body 20, thereby increasing the air outlet velocity and enhancing the ability to resist contaminants. Optionally, a mounting groove is provided on the bottom surface of the baffle body 20 , and the light shielding plate 30 is installed in the mounting groove to reduce the thickness of the entire baffle body 20 .

[0053] Example 2

[0054] This embodiment also provides an objective lens anti-contamination device. Compared to the first embodiment, the structure of the objective lens anti-contamination device provided in this embodiment is substantially the same as that of the first embodiment. The difference is that in this embodiment, the light-transmitting portion includes only a first light-transmitting through-hole, which is directly connected to the receiving groove 12 and is not enclosed by a light-transmitting member 16. In other words, the central area of ​​the air inlet body 10 is directly exposed for light transmission. Because the air curtain protective layer formed by the objective lens anti-contamination device can already fully isolate the objective lens from the workpiece to be photoetched, omitting the light-transmitting member 16 can improve the light transmittance of the photolithography while meeting anti-contamination requirements, while also simplifying the manufacturing process and reducing costs.

[0055] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. An objective lens anti-pollution device, characterized in that: The objective lens anti-pollution device comprises: An air intake body (10), wherein an air intake passage (11) is provided inside the air intake body (10), a receiving groove (12) is provided on the bottom surface of the air intake body (10), and the air intake passage (11) is provided on the periphery of the receiving groove (12); a baffle body (20), the baffle body (20) being placed in the accommodating groove (12), and the top surface of the baffle body (20) being spaced apart from the bottom of the accommodating groove (12); a first outlet flow channel (21) being provided on the top surface of the baffle body (20), a second outlet flow channel (22) being wider at the top and narrower at the bottom being formed through the center of the baffle body (20), the first outlet flow channel (21) being provided around the outer periphery of the second outlet flow channel (22), and being in communication with the inlet flow channel (11); The inlet flow channel (11) is connected to the bottom of the first outlet flow channel (21); the first outlet flow channel (21) has a wedge-shaped structure that is narrow at the top and wide at the bottom.

2. The objective lens anti-pollution device according to claim 1, characterized in that: The second outlet flow channel (22) is a frustum structure.

3. The objective lens anti-pollution device according to claim 1, characterized in that: A circle of first vent holes (13) is provided on the side wall of the inlet flow channel (11) close to the first outlet flow channel (21), and a circle of second vent holes (24) is provided on the side wall of the first outlet flow channel (21) close to the inlet flow channel (11). The number of the first vent holes (13) corresponds to the number of the second vent holes (24), and the first vent holes (13) are connected to the corresponding second vent holes (24).

4. The objective lens anti-pollution device according to claim 3, characterized in that: The baffle body (20) has a first position and a second position that are centrally symmetrical in the circumference, and a third position located between the first position and the second position, wherein the first position is an air inlet position; in the direction from the first position to the third position, the aperture of the second vent hole (24) gradually decreases, and / or the hole depth of the second vent hole (24) gradually becomes longer; in the direction from the third position to the second position, the aperture of the second vent hole (24) gradually increases, and / or the hole depth of the second vent hole (24) gradually decreases.

5. The objective lens anti-pollution device according to claim 3, characterized in that: A buffer flow channel (23) is further provided between the outer peripheral surface of the baffle body (20) and the circumferential groove wall of the accommodating groove (12), and the buffer flow channel (23) is simultaneously communicated with the first vent hole (13) and the second vent hole (24).

6. The objective lens anti-pollution device according to claim 1, characterized in that: A third vent hole is provided on the circumferential side wall of the second outlet flow channel (22), and the third vent hole horizontally connects the first outlet flow channel (21) and the second outlet flow channel (22).

7. The objective lens anti-pollution device according to claim 1, characterized in that: A circle of fourth ventilation holes is provided on the bottom surface of the baffle body (20), and the fourth ventilation holes are connected to the first outlet flow channel (21).

8. The objective lens anti-pollution device according to claim 1, characterized in that: A light-transmitting portion is formed at the center of the air inlet body (10), and light from the objective lens is transmitted to the workpiece to be photoetched via the light-transmitting portion and the second air outlet channel (22) in sequence.

9. The objective lens anti-pollution device according to claim 8, characterized in that: The light-transmitting portion comprises a first light-transmitting through hole formed on the air inlet body (10), the first light-transmitting through hole being in communication with the accommodating groove (12); the first light-transmitting through hole can be sealed by a light-transmitting member (16), or the first light-transmitting through hole is not sealed by the light-transmitting member (16).

10. The objective lens anti-pollution device according to claim 1, characterized in that: The objective lens anti-pollution device further comprises a light shielding plate (30), which is arranged at the bottom of the baffle body (20) and is used to partially shield the hollow area in the center of the baffle body (20) to form a target exposure field of view.

11. The objective lens anti-pollution device according to claim 1, characterized in that: A circle of limiting bosses (25) is circumferentially provided on the bottom of the baffle body (20), and the air inlet body (10) abuts against the limiting bosses (25) to limit the placement depth of the baffle body (20) in the accommodating groove (12).

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