Anti-pollution protection device, objective lens and lithography machine

Abstract

The application discloses a kind of anti-pollution protection device, objective and photoetching machine, belong to semiconductor technical field.The anti-pollution protection device includes field baffle and annular main structure, airflow passes through air inlet sequentially through first annular channel and second annular channel, airflow after entering containing cavity from second annular channel is finally discharged from field window, and the air layer that protects lens from being polluted is formed in containing cavity, so that the light beam can be projected on workpiece after passing through lens, through containing cavity and field window, due to the homogenization treatment in second annular channel and first annular channel, the outflow is more homogenized, avoid local vortex to form pollutant stagnation area;It can also effectively resist lateral wind disturbance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an anti-contamination protection device, an objective lens, and a photolithography machine. Background Technology

[0002] The semiconductor industry is a pillar of the high-tech, information-driven era. Photolithography, which transfers the chip pattern from a photomask to corresponding layers on a silicon wafer through exposure, is considered a core technology in the semiconductor supply chain. However, since the photolithography process takes place inside the lithography machine, contamination from photoresist and organic matter generated during the exposure process on the objective lens surface has consistently hindered the precision of photolithography.

[0003] Air baths are an important means of pollution control. Based on fluid mechanics, by changing the fluid velocity, channel shape, size, or outlet direction, high-speed airflow can be evenly distributed on the objective lens surface, forming an air curtain to prevent contaminants from contacting it. Furthermore, air baths can effectively reduce ambient temperature to prevent photoresist evaporation contamination caused by high temperatures. However, in actual internal channel designs, the outlet airflow cannot be uniformly distributed and is easily disturbed by lateral winds, leading to localized vortices that create areas where contaminants accumulate, severely reducing silicon wafer production efficiency.

[0004] Therefore, there is an urgent need to provide a pollution protection device, objective lens, and lithography machine to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a pollution protection device, objective lens, and lithography machine that provides greater uniformity of the outflow, avoids the formation of local vortices that create pollutant retention areas, and effectively resists lateral wind disturbances.

[0006] To achieve the above objectives, the following technical solution is provided:

[0007] A pollution prevention and protection device, comprising:

[0008] The annular main structure includes a receiving cavity, a first annular channel and a second annular channel arranged sequentially from the inside to the outside. An air inlet is provided through the outer wall of the second annular channel. The second annular channel is connected to the first annular channel. The first annular channel is connected to the receiving cavity. The receiving cavity passes through the annular main structure along the axial direction of the first annular channel.

[0009] A field-of-view baffle is disposed within the receiving cavity and connected to the annular main structure. The field-of-view baffle includes a field-of-view baffle body, on which a field-of-view window is provided. The field-of-view window extends through the field-of-view baffle body along the axial direction of the first annular channel.

[0010] As an optional solution for pollution prevention and protection devices, the second annular channel is provided with a number of connecting holes at intervals around the circumference, and the second annular channel is connected to the first annular channel through the connecting holes.

[0011] As an optional solution for pollution prevention and protection devices, the connecting hole is not coaxial with the air inlet.

[0012] As an optional solution for the pollution prevention and protection device, the first annular channel is provided with a number of nozzles spaced circumferentially, and the first annular channel is connected to the receiving cavity through the nozzles.

[0013] As an optional solution for the pollution prevention and protection device, the field of view baffle also includes an airflow homogenizing plate, which is arranged in a ring on the field of view baffle body. The airflow homogenizing plate and the field of view baffle body are arranged at a first preset angle B, and the height of the upper end surface of the airflow homogenizing plate is not less than the height of the nozzle.

[0014] As an optional solution for pollution prevention and protection devices, the angle between the airflow homogenizing plate and the field of view baffle body is rounded or sharp.

[0015] As an optional solution for the pollution prevention and protection device, an airflow baffle extending towards the center is provided circumferentially on the side of the nozzle away from the field of view baffle on the annular main structure, and there is a gap between the lower end face of the airflow baffle and the upper end face of the airflow homogenizing plate.

[0016] As an optional solution for the pollution prevention and protection device, the field of view baffle also includes an airflow guide plate, which is arranged in a ring on the field of view baffle body. The airflow guide plate and the field of view baffle body are arranged at a second preset angle C, and the height of the airflow guide plate is less than the height of the airflow homogenization plate.

[0017] As an optional solution for the pollution prevention and protection device, the airflow homogenizing plate extends obliquely in the direction close to the nozzle, and the first preset angle B between the airflow homogenizing plate and the field of view baffle body is 25°-85°.

[0018] As an optional solution for the pollution protection device, the airflow guide plate extends obliquely in a direction away from the nozzle, and the second preset angle C between the airflow guide plate and the field of view baffle body is 25°-40°.

[0019] As an optional solution for the pollution prevention and protection device, the outer ring wall of the second annular channel is provided with a first cleaning hole, and the first annular channel is provided with a second cleaning hole.

[0020] As an optional pollution protection device, the air inlet extends radially along the second annular channel.

[0021] An objective lens includes an objective lens and a contamination protection device as described in any of the preceding claims, wherein the objective lens is disposed on the side of the annular main structure away from the field of view baffle, and the objective lens is coaxially arranged with the field of view window.

[0022] A lithography machine, including the aforementioned objective lens.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The anti-pollution protection device provided by this invention includes a field-of-view baffle and an annular main structure. The airflow passes through the air inlet and sequentially through the first annular channel and the second annular channel. After entering the receiving cavity through the second annular channel, the airflow finally exits from the field-of-view window, forming an air layer in the receiving cavity to protect the lens from contamination. This allows the light beam to pass through the lens and be projected onto the workpiece through the receiving cavity and the field-of-view window. Due to the homogenization through the second annular channel and the first annular channel, the outflow is more uniform, avoiding the formation of local vortices that create areas where pollutants are trapped. It can also effectively resist lateral wind disturbances.

[0025] The objective lens provided by the present invention has the objective lens positioned on the side of the annular main structure away from the field of view baffle 1. By forming a fully homogenized and lateral disturbance-resistant protective gas layer in the cavity, the cleanliness of the objective lens surface is improved.

[0026] The lithography machine provided by this invention can form a fully homogenized protective gas layer on the surface of the objective lens to be protected, which is resistant to lateral disturbances, thus ensuring the etching accuracy of the lithography machine. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the assembly of the pollution prevention protection device in an embodiment of the present invention;

[0029] Figure 2 This is an explosion diagram of the pollution prevention protection device in an embodiment of the present invention;

[0030] Figure 3 This is a cross-sectional view of the anti-pollution protection device in an embodiment of the present invention;

[0031] Figure 4 This is a cross-sectional view of the annular main structure in an embodiment of the present invention;

[0032] Figure 5 for Figure 4 Enlarged view of a portion of point A in the middle;

[0033] Figure 6 This is a cross-sectional view of the field-of-view baffle body in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the first structure of the field of view window in an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of the second structure of the field of view window in an embodiment of the present invention;

[0036] Figure 9 This is a bottom view of the annular main structure in an embodiment of the present invention.

[0037] Figure label:

[0038] 1. Field of view baffle; 2. Annular main structure; 3. First powder cleaning hole; 4. Second powder cleaning hole; 5. First mounting hole; 6. Second mounting hole; 7. Sealing head;

[0039] 11. Field of view baffle body; 12. Field of view window; 13. Airflow homogenizing plate; 14. Airflow guide plate;

[0040] 21. Receiving cavity; 22. First annular channel; 221. Nozzle; 23. Second annular channel; 231. Air inlet; 232. Connecting hole; 24. Airflow baffle. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] To achieve greater uniformity of the exhaust airflow, prevent the formation of localized vortices that trap pollutants, and effectively resist lateral wind disturbances, this embodiment provides a pollution protection device, which is described below in conjunction with... Figures 1 to 9 The specific content of this embodiment will be described in detail.

[0049] like Figures 1 to 5As shown, the pollution prevention and protection device includes a field-of-view baffle 1 and an annular main structure 2. The annular main structure 2 includes a receiving cavity 21, a first annular channel 22, and a second annular channel 23 arranged sequentially from the inside to the outside. An air inlet 231 is provided through the outer wall of the second annular channel 23. Figure 4 Combination Figure 5 As shown, the second annular channel 23 is connected to the first annular channel 22, and the first annular channel 22 is connected to the receiving cavity 21. Since the receiving cavity 21 penetrates the annular main structure 2 along the axial direction of the first annular channel 22, airflow enters from the air inlet 231 and exits from the receiving cavity 21. The cross-section of the receiving cavity 21 can be, but is not limited to, circular, elliptical, rectangular, or irregular shapes, but is preferably circular. A field-of-view baffle 1 is disposed within the receiving cavity 21 and connected to the annular main structure 2. The field-of-view baffle 1 can be detachably connected to the annular main structure 2. The field-of-view baffle 1 includes a field-of-view baffle body 11, on which a field-of-view window 12 is opened. The field-of-view window 12 penetrates the field-of-view baffle body 11 along the axial direction of the first annular channel 22. The field-of-view window 12 is opened on the field-of-view baffle body 11, and the final field-of-view shape is determined by the shape of the field-of-view window 12. Since the field of view baffle 1 is set inside the receiving cavity 21, the field of view window 12 is positioned opposite to the receiving cavity 21 to avoid blocking the light.

[0050] For example, the air inlet 231 extends radially along the second annular channel 23, facilitating rapid airflow into the second annular channel 23. The airflow flows in through the air inlet 231 and eventually exits through the field of view window 12. The initial direction of the airflow into the anti-pollution protection device is perpendicular to the final direction of its exit from the anti-pollution protection device, thereby homogenizing the clean and dry gas outflow onto the surface of the optical glass and forming a protective gas layer resistant to lateral disturbances. In this embodiment, the optical glass is an objective lens.

[0051] In summary, the pollution protection device provided by this invention includes a field-of-view baffle 1 and an annular main structure 2. The annular main structure 2 has two interconnected flow channels, namely a first annular channel 22 and a second annular channel 23, thereby avoiding the problem that a single channel cannot adequately homogenize the airflow velocity. In other examples, the annular main structure 2 may also have more than two sequentially interconnected flow channels, such as three, four, five, or six sequentially interconnected flow channels.

[0052] In other embodiments, the centers of the second annular channel 23 and the first annular channel 22 in the vertical direction may be at the same height or at different heights. The longitudinal cross-sections of the second annular channel 23 and the first annular channel 22 may be, but are not limited to, circular, elliptical, rectangular, and irregular shapes. Preferably, the longitudinal cross-sectional area of ​​the first annular channel 22 is greater than the longitudinal cross-sectional area of ​​the second annular channel 23.

[0053] Furthermore, such as Figure 5 As shown, a plurality of connecting holes 232 or connecting channels are circumferentially spaced in the second annular channel 23. The second annular channel 23 is connected to the first annular channel 22 through the connecting holes 232 or connecting channels. By adjusting the number and position height of the connecting holes 232, the airflow homogenization effect is further enhanced. Specifically, the air inlet surface of the connecting holes 232 or connecting channels faces the inner cavity of the second annular channel 23, and the air outlet surface of the connecting holes 232 or connecting channels faces the inner cavity of the first annular channel 22.

[0054] In some application scenarios, the connecting channels can be multiple disconnected channels or continuous channels. The vertical height of the air outlet surface of the connecting channel can be adjusted according to the airflow velocity distribution requirements.

[0055] In some application scenarios, the extension direction of the connecting hole 232 or the connecting channel can be horizontal, or it can have a certain angle with the horizontal plane, or it can be an irregular serpentine direction, etc.

[0056] For example, a plurality of connecting holes 232 are provided in a wavy pattern along the extension direction of the second annular channel 23.

[0057] For example, multiple connecting holes 232 can be located on the same horizontal plane or arranged in a staggered manner, without much restriction here.

[0058] Preferably, the air inlet 231 and the connecting hole 232 are not coaxially arranged. That is, after the airflow flows into the second annular channel 23 from the air inlet 231, it does not flow directly into the first annular channel 22 from the connecting hole 232. Instead, it first encounters the side wall corresponding to the air inlet 231, which serves to divert the flow. Specifically, the air inlet 231 and the connecting hole 232 are not correspondingly arranged.

[0059] The connecting holes 232 on the second annular channel 23 are not uniformly distributed in size; their size and distribution can be adjusted according to the requirements of the outflow velocity distribution. The first annular channel 22 is circumferentially spaced with several nozzles 221. The first annular channel 22 is connected to the receiving cavity 21 through the nozzles 221. The airflow passes through the inlet 231, sequentially through the second annular channel 23 and the first annular channel 22, and exits from the nozzles 221 of the first annular channel 22. After entering the receiving cavity 21, the airflow finally exits through the field of view window 12, forming an air layer within the receiving cavity 21 that protects the lens from contamination. This allows the light beam to pass through the lens and be projected onto the workpiece through the receiving cavity 21 and the field of view window 12. Because the second annular channel 23 is circumferentially spaced with several connecting holes 232, and the first annular channel 22 is circumferentially spaced with several nozzles 221, the size and distribution of the nozzles 221 can be adjusted according to the requirements of the outflow velocity distribution, resulting in a more uniform outflow velocity and preventing localized vortices that could trap contaminants. The circumferential arrangement of the nozzles 221 also effectively resists lateral wind disturbances.

[0060] In some applications, multiple nozzles 221 are set one-to-one with multiple connecting holes 232 to balance the airflow uniformity and flow rate.

[0061] In some applications, the nozzle 221 is not configured in a one-to-one correspondence with the several connecting holes 232, which is beneficial for secondary homogenization of the airflow. The nozzle 221 can be, but is not limited to, circular, elliptical, rectangular, and irregular shapes. Preferably, the nozzle 221 is circular.

[0062] Furthermore, the field of view baffle 1 also includes an airflow homogenizing plate 13, which is arranged in a ring on the field of view baffle body 11. The height of the upper end face of the airflow homogenizing plate 13 is not less than the height of the nozzle 221, so that the airflow ejected from the nozzle 221 meets the front face of the airflow homogenizing plate 13, thereby further homogenizing the airflow ejected from the nozzle 221 and improving the homogenization degree of the airflow.

[0063] Furthermore, on the annular main structure 2, an airflow baffle 24 extending towards the center is provided circumferentially on the side of the nozzle 221 away from the field of view baffle 1. There is a gap between the lower end face of the airflow baffle 24 and the upper end face of the airflow homogenization plate 13 to generate an air curtain protective layer, so that the outflow is in a laminar flow state, ensuring the cleanliness of the lens surface.

[0064] The airflow baffle 24 is annular in shape. The shape of the airflow baffle 24 can be set according to the homogenization requirements. Preferably, the airflow baffle 24 is annular in shape.

[0065] For example, the field of view baffle body 11 is a circular plate structure, and the airflow baffle 24 is parallel to the field of view baffle 11.

[0066] Furthermore, the airflow baffle 24 and the annular main structure 2 are integrated into one structure, which enhances the structural strength.

[0067] Furthermore, such as Figure 6 As shown, the field-of-view baffle 1 also includes an airflow guide plate 14. Both the airflow homogenizing plate 13 and the airflow guide plate 14 are arranged in a ring on the same side of the field-of-view baffle body 11. The airflow homogenizing plate 13 is set at a first preset angle B with the field-of-view baffle body 11, and the airflow guide plate 14 is set at a second preset angle C with the field-of-view baffle body 11. Specifically, the first preset angle B is the angle between the airflow homogenizing plate 13 and the plane of the left side portion of the field-of-view baffle body 11; the second preset angle C is the angle between the airflow guide plate 14 and the plane of the right side portion of the field-of-view baffle body 11. The range of the first preset angle B is 0-180°, and the range of the second preset angle C is 0-180°.

[0068] The angle between the airflow homogenizing plate 13 and the field of view baffle body 11 is rounded or sharp, which facilitates the adjustment of airflow and reduces flow resistance.

[0069] Furthermore, such as Figure 3 and Figure 6 As shown, the airflow homogenizing plate 13 extends obliquely along the direction close to the nozzle 221, and the first preset angle B between the airflow homogenizing plate 13 and the field-of-view baffle body 11 is 25°-85°. Preferably, the first preset angle B between the airflow homogenizing plate 13 and the field-of-view baffle body 11 is 60-75°. Through the cooperation of the airflow homogenizing plate 13, the airflow baffle 24, and the airflow guide plate 14, vortices caused by uneven flow velocity distribution are avoided in the receiving cavity 21, thus creating a clean gas protective layer in the receiving cavity 21 that is resistant to contamination and lateral disturbance.

[0070] Furthermore, such as Figure 3 and Figure 6 As shown, the airflow guide plate 14 extends obliquely in a direction away from the nozzle 221, and the second preset angle C between the airflow guide plate 14 and the field-of-view baffle body 11 is 25°-40°. Preferably, the second preset angle C between the airflow guide plate 14 and the plane of the field-of-view baffle body 11 is in the range of 27°-38°. In other embodiments, the height and tilt angle of the airflow guide plate 14 can be designed and changed according to the required size of the gas protection layer and the requirements for resistance to lateral disturbances.

[0071] Specifically, in this embodiment, the height of the airflow guide plate 14 is less than the height of the airflow homogenizing plate 13, facilitating rapid airflow convergence. After homogenization, the gas flows out from the gap between the airflow baffle 24 and the airflow homogenizing plate 13. Part of the airflow flows parallel to the airflow baffle 24 in a laminar flow, while another part flows along the back of the airflow homogenizing plate 13, the upper surface of the field-of-view baffle body 11, and the back of the airflow guide plate 14. Then, the two parts of the airflow converge, making the outflow state laminar, and finally flowing out from the field-of-view window 12. Installing the anti-pollution protection device on the optical glass can form a protective gas layer that resists lateral disturbances on the surface of the optical glass to be protected.

[0072] Specifically, the gap between the airflow baffle 24 and the airflow homogenizing plate 13 is set to 0.5mm-2mm. Preferably, the gap between the airflow baffle 24 and the airflow homogenizing plate 13 needs to be set to within 1mm-1.5mm to ensure that the outlet airflow velocity is fully homogenized and distributed.

[0073] The field of view window 12 can be selected with openings of different shapes to meet optical design requirements. In some applications, such as... Figure 7 As shown, the field of view window 12 is square in shape. In other application scenarios, such as... Figure 8 As shown, the field of view window 12 is rectangular in shape. The field of view window 12 is adapted to the emitted rays of the optical glass and does not obstruct them.

[0074] Furthermore, such as Figure 2 As shown, the outer ring wall of the second annular channel 23 is provided with a first powder cleaning hole 3. Furthermore, as... Figure 9 As shown, a second cleaning hole 4 is provided on the first annular channel 22. During the use of the anti-pollution protection device, both the first cleaning hole 3 and the second cleaning hole 4 are blocked. After using the anti-pollution protection device for a certain period of time, the air gun is connected to the first cleaning hole 3 and the second cleaning hole 4 to blow air out, thoroughly blowing out the sediment or dust inside the anti-pollution protection device, thus completing the cleaning work.

[0075] Specifically, the second annular channel 23 is provided with a first powder cleaning hole 3, and two spaced-apart second powder cleaning holes 4 are provided below the first annular channel 22.

[0076] Furthermore, such as Figure 2 and 9 As shown, a first mounting hole 5 is provided on the first annular channel 22, and a second mounting hole 6 is provided on the field-of-view baffle body 11. The first mounting hole 5 and the second mounting hole 6 are correspondingly provided, and the field-of-view baffle body 11 is connected to the first mounting hole 5 by fasteners. Specifically, the first mounting hole 5 is a threaded hole. There are multiple first mounting holes 5. Specifically, there are four first mounting holes 5, which are evenly spaced below the first annular channel 22.

[0077] Furthermore, such as Figure 9 As shown, the first mounting hole 5 and the second powder cleaning hole 4 are located on the same side of the first annular channel 22. Figure 2 As shown, a sealing head 7 protrudes from the field-of-view baffle body 11, and the sealing head 7 is correspondingly arranged with the second powder cleaning hole 4. When the field-of-view baffle body 11 is installed on the annular main structure 2, the sealing head 7 is sealed and inserted into the second powder cleaning hole 4.

[0078] This embodiment also provides an objective lens, including an objective lens and the aforementioned anti-contamination protection device. The objective lens is disposed on the side of the annular main structure 2 away from the field of view baffle 1, and the objective lens is coaxially disposed with the field of view window 12 to avoid blocking light. The cleanliness of the objective lens surface is improved by the fully homogenized and lateral disturbance resistant protective gas layer formed in the receiving cavity 21.

[0079] This embodiment also provides a lithography machine, including the above-mentioned anti-contamination protection device, with the field window 12 being a rectangular opening, and the anti-contamination protection device being detachably connected to the objective lens.

[0080] The principle of this device is as follows: Clean Dry Gas (CDA) first flows into the second annular channel 23 from the inlet 231, changing its flow direction and distributing evenly within the channel. Through the uneven distribution of multiple connecting holes 232, a uniform outlet gas velocity is generated, flowing into the first annular channel 22. The first annular channel 22 further homogenizes the outlet gas velocity through nozzles 221 with unevenly distributed orifices and an airflow homogenizing plate 13. To ensure the outlet gas velocity, the optimized outlet gas velocity of the nozzles 221 should be maintained within the range of 0.7 m / s to 1 m / s, and the number of internal holes and the inlet gas velocity are set within this range. The design of the interaction between the second annular channel 23, the first annular channel 22, and the airflow homogenizing plate 13 maximizes the uniform distribution of the outlet gas velocity while ensuring its uniformity, and keeps the outlet gas in a laminar flow state, thereby forming an air protective layer that resists lateral disturbances. At the same time, positive pressure gas is generated in the containment cavity 21 to ensure that pollutants are difficult to enter the device. Under the condition of lateral disturbance, the semi-enclosed containment cavity 21 is the design theoretical basis for the device to effectively maintain the anti-pollution performance of the device (keeping the surface contamination of the optical glass below 0.5%).

[0081] Note that the above description is merely a preferred embodiment 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 various obvious changes, readjustments, and substitutions can be made 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 which is determined by the scope of the appended claims.

Claims

1. A pollution prevention and protection device, characterized in that, include: The annular main structure (2) includes a receiving cavity (21), a first annular channel (22) and a second annular channel (23) arranged sequentially from the inside to the outside. An air inlet (231) is provided through the outer wall of the second annular channel (23). The second annular channel (23) is connected to the first annular channel (22). A plurality of nozzles (221) are arranged circumferentially on the first annular channel (22). The first annular channel (22) is connected to the receiving cavity (21) through the nozzles (221). The receiving cavity (21) passes through the annular main structure (2) along the axial direction of the first annular channel (22). A field of view baffle (1) is disposed in the receiving cavity (21) and connected to the annular main structure (2). The field of view baffle (1) includes a field of view baffle body (11). A field of view window (12) is provided on the field of view baffle body (11). The field of view window (12) passes through the field of view baffle body (11) along the axial direction of the first annular channel (22). The field of view baffle (1) further includes an airflow homogenizing plate (13), which is arranged in a ring on the field of view baffle body (11). The airflow homogenizing plate (13) and the field of view baffle body (11) are arranged at a first preset angle B. The height of the upper end surface of the airflow homogenizing plate (13) is not less than the height of the nozzle (221). The airflow homogenizing plate (13) extends obliquely in the direction close to the nozzle (221). An airflow baffle (24) extending toward the center is provided circumferentially on the side of the nozzle (221) away from the field baffle (1) on the annular main structure (2), and there is a gap between the lower end face of the airflow baffle (24) and the upper end face of the airflow homogenizing plate (13).

2. The pollution prevention and protection device according to claim 1, characterized in that, The second annular channel (23) is provided with a plurality of connecting holes (232) spaced circumferentially, and the second annular channel (23) is connected to the first annular channel (22) through the connecting holes (232).

3. The pollution prevention and protection device according to claim 2, characterized in that, The connecting hole (232) and the air inlet (231) are not coaxially arranged.

4. The pollution prevention and protection device according to claim 1, characterized in that, The angle between the airflow homogenizing plate (13) and the field of view baffle body (11) is rounded or sharp.

5. The pollution prevention and protection device according to claim 1, characterized in that, The field of view baffle (1) also includes an airflow guide plate (14), which is arranged in a ring on the field of view baffle body (11). The airflow guide plate (14) and the field of view baffle body (11) are arranged at a second preset angle C. The height of the airflow guide plate (14) is less than the height of the airflow homogenizing plate (13).

6. The pollution prevention and protection device according to claim 5, characterized in that, The first preset angle B between the airflow homogenizing plate (13) and the field of view baffle body (11) is 25°-85°.

7. The pollution prevention and protection device according to claim 5, characterized in that, The airflow guide plate (14) extends obliquely away from the nozzle (221), and the second preset angle C between the airflow guide plate (14) and the field of view baffle body (11) is 25°-40°.

8. The pollution prevention and protection device according to claim 1, characterized in that, The outer ring wall of the second annular channel (23) is provided with a first cleaning hole (3), and the first annular channel (22) is provided with a second cleaning hole (4).

9. The pollution prevention and protection device according to claim 2, characterized in that, The air inlet (231) extends radially along the second annular channel (23).

10. An objective lens, characterized in that, Includes an objective lens and a pollution protection device as described in any one of claims 1-9, wherein the objective lens is disposed on the side of the annular main structure (2) away from the field of view baffle (1), and the objective lens is coaxially disposed with the field of view window (12).

11. A lithography machine, characterized in that, Includes the objective lens as described in claim 10.

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