CN116736640A

CN116736640A - Anti-pollution protection device, objective lens and photoetching machine

Info

Publication number: CN116736640A
Application number: CN202210195403.0A
Authority: CN
Inventors: 洪国; 湛宾洲; 程斌斌; 王成; 杨若霁; 李运锋
Original assignee: Shanghai Micro Electronics Equipment Co Ltd
Current assignee: Shanghai Micro Electronics Equipment Co Ltd
Priority date: 2022-03-01
Filing date: 2022-03-01
Publication date: 2023-09-12

Abstract

The invention discloses an anti-pollution protection device, an objective lens and a photoetching machine, and belongs to the technical field of semiconductors. The anti-pollution protection device comprises a view field baffle and an annular main body structure, wherein air flow sequentially passes through a first annular channel and a second annular channel through an air inlet, the air flow entering a containing cavity from the second annular channel is finally discharged from a view field window, and an air layer for protecting a lens from being polluted is formed in the containing cavity, so that a light beam can be projected onto a workpiece through the containing cavity and the view field window after passing through the lens, and the air flow is more homogenized due to homogenization treatment in the second annular channel and the first annular channel, so that local vortex generation is avoided to form a pollutant retention area; and the cross wind disturbance can be effectively resisted.

Description

Anti-pollution protection device, objective lens and photoetching machine

Technical Field

The invention relates to the technical field of semiconductors, in particular to an anti-pollution protection device, an objective lens and a photoetching machine.

Background

The semiconductor industry is a support in the high-tech, information-oriented age. The photolithography technique for manufacturing the required chip is considered as a core technique in the semiconductor industry chain, in which the chip pattern on the mask plate is sequentially transferred to the corresponding layer of the silicon wafer through exposure. However, the photolithography process is inside the photolithography machine, and organic contamination on the objective lens surface due to photoresist and exposure process always hinders the photolithography accuracy.

Gas bath devices are one of the important means of pollution control. Based on fluid mechanics, high-speed air inlet flow can be uniformly distributed on the surface of the objective lens by changing the flow velocity, the flow channel shape, the size or the air outlet direction of fluid, so that an air curtain is formed, and pollution is prevented from contacting. In addition, the gas bath can also effectively reduce the ambient temperature so as to prevent the occurrence of photoresist volatilization pollution caused by high temperature. However, in the actual internal flow channel design, the air flow cannot be homogenized, and is disturbed by lateral wind, so that vortex is easily generated locally to form a pollutant retention area, and the production efficiency of the silicon wafer is seriously reduced.

For this reason, it is necessary to provide a contamination protection device, an objective lens, and a lithographic apparatus to solve the above-mentioned problems.

Disclosure of Invention

The invention aims to provide an anti-pollution protection device, an objective lens and a photoetching machine, which are capable of enabling air flow to be more uniform, avoiding local vortex to form a pollutant retention area and effectively resisting lateral wind disturbance.

In order to achieve the above object, the following technical scheme is provided:

an anti-pollution protection device, comprising:

the annular main body structure comprises a containing cavity, a first annular channel and a second annular channel which are sequentially arranged from inside to outside, wherein an air inlet is formed in the outer wall of the second annular channel in a penetrating manner, the second annular channel is communicated with the first annular channel, the first annular channel is communicated with the containing cavity, and the containing cavity penetrates through the annular main body structure along the axial direction of the first annular channel;

the view field baffle is arranged in the accommodating cavity and is connected with the annular main body structure, the view field baffle comprises a view field baffle body, a view field window is formed in the view field baffle body, and the view field window penetrates through the view field baffle body along the axial direction of the first annular channel.

As an alternative scheme of the anti-pollution protection device, a plurality of communication holes are circumferentially arranged on the second annular channel at intervals, and the second annular channel is communicated with the first annular channel through the communication holes.

As an alternative to the anti-pollution protection device, the communication hole is arranged non-coaxially with the air inlet.

As an alternative of the anti-pollution protection device, a plurality of nozzles are circumferentially arranged on the first annular channel at intervals, and the first annular channel is communicated with the accommodating cavity through the nozzles.

As an alternative scheme of the anti-pollution protection device, the visual field baffle further comprises an airflow homogenizing plate, the airflow homogenizing plate is annularly arranged on the visual field baffle body, the airflow homogenizing plate and the visual field baffle body are arranged at a first preset included angle B, and the height of the upper end face of the airflow homogenizing plate is not smaller than the height of the nozzle.

As an alternative scheme of the anti-pollution protection device, the included angle between the airflow homogenizing plate and the view field baffle body is a round angle or a sharp angle.

As an alternative scheme of the anti-pollution protection device, an airflow baffle plate extending towards the center is circumferentially arranged on one side, far away from the view field baffle plate, of the annular main body structure, and a gap exists between the lower end face of the airflow baffle plate and the upper end face of the airflow homogenizing plate.

As an alternative scheme of the anti-pollution protection device, the view field baffle further comprises an airflow guide plate, the airflow guide plate is annularly arranged on the view field baffle body, the airflow guide plate and the view field baffle body are arranged at a second preset included angle C, and the height of the airflow guide plate is smaller than that of the airflow homogenizing plate.

As an alternative to the anti-pollution protection device, the air flow homogenizing plate extends obliquely in a direction approaching the nozzle, and the first preset included angle B between the air flow homogenizing plate and the view field baffle body is 25 ° -85 °.

As an alternative to the anti-pollution protection device, the airflow deflector extends obliquely in a direction away from the nozzle, and a second preset included angle C between the airflow deflector and the view field baffle body is 25 ° -40 °.

As an alternative scheme of the anti-pollution protection device, the outer annular wall of the second annular channel is provided with a first powder cleaning hole in a penetrating mode, and the first annular channel is provided with a second powder cleaning hole.

As an alternative to the contamination protection arrangement, the air inlet extends in a radial direction of the second annular channel.

An objective lens comprising an objective lens and an anti-pollution protection device according to any one of the above, wherein the objective lens is arranged on one side of the annular main body structure far away from the view field baffle, and the objective lens and the view field window are coaxially arranged.

A photoetching machine comprises the objective lens.

Compared with the prior art, the invention has the beneficial effects that:

the anti-pollution protection device provided by the invention comprises the view field baffle and the annular main body structure, the air flow sequentially passes through the first annular channel and the second annular channel through the air inlet, the air flow entering the accommodating cavity through the second annular channel is finally discharged from the view field window, and an air layer for protecting the lens from pollution is formed in the accommodating cavity, so that the light beam can be projected onto a workpiece through the accommodating cavity and the view field window after passing through the lens, and the air flow is more homogenized through the second annular channel and the first annular channel, so that the pollutant retention area formed by local vortex is avoided, and the lateral wind disturbance can be effectively resisted.

According to the objective lens provided by the invention, the objective lens is arranged on one side of the annular main body structure, which is far away from the view field baffle plate 1, and the cleanliness of the surface of the objective lens is improved through the fully-homogenized and laterally-disturbance-resistant protective gas layer formed in the accommodating cavity.

The photoetching machine provided by the invention can form a fully homogenized protective air layer which can resist lateral disturbance on the surface of an objective lens to be protected, and ensures the etching precision of the photoetching machine.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following description will briefly explain the drawings needed in the description of the embodiments of the present invention, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the contents of the embodiments of the present invention and these drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram illustrating the assembly of an anti-pollution protection device according to an embodiment of the present invention;

FIG. 2 is an exploded view of an anti-pollution protection device according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view of an anti-pollution protection device in an embodiment of the invention;

FIG. 4 is a cross-sectional view of an annular body structure in an embodiment of the invention;

FIG. 5 is an enlarged view of a portion of FIG. 4 at A;

FIG. 6 is a cross-sectional view of a field shield body according to an embodiment of the present invention;

FIG. 7 is a schematic view of a first structure of a view field window according to an embodiment of the present invention;

FIG. 8 is a schematic view of a second structure of a view field window according to an embodiment of the present invention;

fig. 9 is a schematic bottom view of the annular main structure according to the embodiment of the present invention.

Reference numerals:

1. a field baffle; 2. an annular main body structure; 3. a first powder cleaning hole; 4. a second powder cleaning hole; 5. a first mounting hole; 6. a second mounting hole; 7. a blocking head;

11. a field baffle body; 12. a field window; 13. an air flow homogenizing plate; 14. an airflow deflector;

21. a receiving chamber; 22. a first annular channel; 221. a nozzle; 23. a second annular channel; 231. an air inlet; 232. a communication hole; 24. an air flow baffle.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed", "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected or integrally connected; either mechanically or electrically. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In order to make the air flow more uniform, avoid forming a pollutant retention area by local vortex, and effectively resist side wind disturbance, the present embodiment provides an anti-pollution protection device, and details of the present embodiment are described in detail below with reference to fig. 1 to 9.

As shown in fig. 1 to 5, the anti-pollution protection device comprises a view field baffle 1 and an annular main body structure 2, wherein the annular main body structure 2 comprises a containing cavity 21, a first annular channel 22 and a second annular channel 23 which are sequentially arranged from inside to outside, and an air inlet 231 is formed in the outer wall of the second annular channel 23 in a penetrating manner. As shown in fig. 4 in combination with fig. 5, the second annular passage 23 communicates with the first annular passage 22, and the first annular passage 22 communicates with the accommodation chamber 21. Since the accommodating chamber 21 penetrates the annular main body structure 2 in the axial direction of the first annular passage 22, the air flow is caused to flow in from the air inlet 231 and flow out from the accommodating chamber 21, and the cross section of the accommodating chamber 21 may be, but is not limited to, circular, elliptical, rectangular, irregularly shaped, etc., and the cross section of the accommodating chamber 21 is preferably circular. The view field baffle 1 is arranged in the accommodating cavity 21 and is connected with the annular main body structure 2, and the view field baffle 1 can be detachably connected with the annular main body structure 2. The view field baffle 1 comprises a view field baffle body 11, a view field window 12 is formed in the view field baffle body 11, and the view field window 12 penetrates through the view field baffle body 11 along the axial direction of the first annular channel 22. The view field window 12 is opened on the view field baffle body 11, and the final view field shape is determined by the shape of the view field window 12. Since the view field baffle 1 is arranged in the accommodating cavity 21, the view field window 12 and the accommodating cavity 21 are arranged oppositely, and light is prevented from being blocked.

Illustratively, the air inlet 231 extends radially of the second annular channel 23 to facilitate rapid flow of air into the second annular channel 23. The air flow flows in from the air inlet 231 and finally is discharged from the view field window 12, and the direction of the air flow initially flowing into the anti-pollution protection device is perpendicular to the direction of the air flow finally discharged from the anti-pollution protection device, so that homogenized clean and dry air flows out of the surface of the optical glass and a protective air layer capable of resisting lateral disturbance is formed, and the optical glass in the embodiment is an objective lens.

In short, the anti-pollution protection device provided by the invention comprises the view field baffle 1 and the annular main body structure 2, wherein two inner and outer flow passages are distributed in the annular main body structure 2, and the two inner and outer flow passages are respectively a first annular passage 22 and a second annular passage 23 which are communicated with each other, so that the problem that the flow rate of the air outlet cannot be fully homogenized by a single passage is avoided. In other examples, the annular main body structure 2 may further have more than two sequentially communicated channels distributed therein, and may have three, four, five, six, etc. sequentially communicated channels.

In other embodiments, the centers of the second annular channel 23 and the first annular channel 22 in the vertical direction may be the same height, or may be different heights, and the longitudinal sections of the second annular channel 23 and the first annular channel 22 may be, but are not limited to, circular, elliptical, rectangular, irregularly shaped, etc., preferably, the longitudinal section area of the first annular channel 22 is larger than the longitudinal section area of the second annular channel 23.

Further, as shown in fig. 5, a plurality of communication holes 232 or communication channels are circumferentially arranged on the second annular channel 23 at intervals, the second annular channel 23 is communicated with the first annular channel 22 through the communication holes 232 or the communication channels, and the homogenization effect of the air flow is further increased by adjusting the number and the position height of the communication holes 232. Specifically, the air inlet surface of the communication hole 232 or the communication passage faces the inner cavity of the second annular passage 23, and the air outlet surface of the communication hole 232 or the communication passage faces the inner cavity of the first annular passage 22.

In some application scenarios, the communication channel may be a plurality of disconnected channels or may be a continuous channel, and the height of the air outlet surface of the communication channel in the vertical direction may be adjusted according to the air outlet flow velocity distribution requirement.

In some application scenarios, the extending direction of the communicating hole 232 or the communicating channel may be horizontal, or may have a certain included angle with the horizontal plane, or may be an irregular serpentine trend, etc.

Illustratively, a plurality of communication holes 232 are provided in a wavy shape along the extending direction of the second annular passage 23.

Illustratively, the plurality of communication holes 232 may be located on the same horizontal plane or may be arranged in a staggered manner up and down, without being limited thereto.

Preferably, the air inlet 231 is disposed non-coaxially with the communication hole 232, i.e., the air flow does not directly flow from the communication hole 232 into the first annular channel 22 after flowing from the air inlet 231 into the second annular channel 23, but meets the corresponding sidewall of the air inlet 231, thereby serving as a split flow. Specifically, the air intake 231 is not provided corresponding to the communication hole 232.

The communicating holes 232 on the second annular channel 23 are not uniformly distributed in size, and the pore size and distribution can be adjusted according to the distribution requirement of the outlet flow velocity. The first annular channel 22 is circumferentially provided with a plurality of nozzles 221 at intervals, the first annular channel 22 is communicated with the accommodating cavity 21 through the nozzles 221, air flows sequentially pass through the second annular channel 23 and the first annular channel 22 through the air inlet 231, are sprayed out from the plurality of nozzles 221 of the first annular channel 22, and finally are discharged from the view field window 12, an air layer for protecting the lens from being polluted is formed in the accommodating cavity 21, so that the light beams can pass through the accommodating cavity 21 and the view field window 12 to be projected onto a workpiece after passing through the lens, and as a plurality of communication holes 232 are circumferentially arranged on the second annular channel 23 at intervals, a plurality of nozzles 221 are circumferentially arranged on the first annular channel 22 at intervals, the aperture size and the distribution of the nozzles 221 can be adjusted according to the distribution requirement of the air flow, so that the air flow is more uniform, and a pollutant retention area formed by vortex is avoided; the circumferential arrangement of the plurality of nozzles 221 is also effective against cross wind disturbances.

In some application scenarios, the plurality of nozzles 221 and the plurality of communication holes 232 are arranged in a one-to-one correspondence manner, and both the homogenizing effect and the flow velocity of the air flow are considered.

In some application scenarios, the nozzles 221 and the communication holes 232 are not arranged in a one-to-one correspondence, which is beneficial to secondary homogenization of the air flow. The nozzle 221 may be, but is not limited to being, circular, elliptical, rectangular, irregularly shaped, etc. Preferably, the nozzle 221 is circular.

Further, the view field baffle 1 further includes an airflow homogenizing plate 13, the airflow homogenizing plate 13 is annularly disposed on the view field baffle body 11, and the height of the upper end surface 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 surface of the airflow homogenizing plate 13, and the airflow ejected from the nozzle 221 is further homogenized, so that the homogenization degree of the airflow is improved.

Further, an airflow baffle 24 extending towards the center is circumferentially arranged on one side of the nozzle 221 away from the view field baffle 1 on the annular main body structure 2, and a gap exists between the lower end surface of the airflow baffle 24 and the upper end surface of the airflow homogenizing plate 13 for generating an air curtain protection layer, so that the airflow is in a laminar state, and the cleaning of the lens surface is ensured.

The airflow baffle 24 is annular in shape. The airflow baffle 24 may be shaped according to the homogenization requirements. Preferably, the airflow baffle 24 is annular in shape.

Illustratively, the viewing field baffle body 11 is a circular plate-like structure, and the airflow baffle 24 and the viewing field baffle 11 are parallel to each other.

And the air flow baffle 24 and the annular main body structure 2 are of an integrated structure, so that the structural strength is enhanced.

Further, as shown in fig. 6, the view field baffle 1 further includes an airflow guide plate 14, the airflow homogenizing plate 13 and the airflow guide plate 14 are all annularly disposed on the same side of the view field baffle body 11, the airflow homogenizing plate 13 and the view field baffle body 11 are disposed at a first preset included angle B, and the airflow guide plate 14 and the view field baffle body 11 are disposed at a second preset included angle C. Specifically, the first preset included angle B is an included angle between the airflow homogenizing plate 13 and a plane of the left part of the view field baffle body 11; the second preset included angle C is an included angle between the airflow deflector 14 and a plane of the right portion of the view-field baffle body 11. The first preset included angle B ranges from 0 to 180 degrees, and the second preset included angle C ranges from 0 to 180 degrees.

The included angle between the airflow homogenizing plate 13 and the view field baffle body 11 is a round angle or a sharp angle, so that the flow of the airflow can be conveniently regulated, and the flow resistance is reduced.

Further, as shown in fig. 3 and 6, the air flow homogenizing plate 13 is extended obliquely in a direction approaching the nozzle 221, and the first preset angle B between the air flow homogenizing plate 13 and the field shield body 11 is 25 ° -85 °. Preferably, the first preset included angle B between the air flow homogenizing plate 13 and the field baffle body 11 is 60-75 °. Through the mutual matching of the airflow homogenizing plate 13, the airflow baffle 24 and the airflow guide plate 14, vortex caused by uneven flow velocity distribution is avoided in the accommodating cavity 21, so that a clean gas protection layer with pollution resistance and lateral disturbance resistance is generated in the accommodating cavity 21 of the device.

Further, as shown in fig. 3 and 6, the air flow deflector 14 extends obliquely in a direction away from the nozzle 221, and the second preset included angle C between the air flow deflector 14 and the field stop body 11 is 25 ° -40 °. Preferably, the second preset included angle C between the airflow deflector 14 and the plane of the view-field baffle body 11 is in the range of 27-38 degrees. In other embodiments, the height and inclination angle of the airflow baffle 14 can be varied according to the design of the gas protection layer and the lateral disturbance resistance.

Specifically, in the present embodiment, the height of the airflow deflector 14 is smaller than the height of the airflow homogenizing plate 13, so that the airflows are quickly converged. After the gas is homogenized, the gas flows out from the gap between the gas flow baffle 24 and the gas flow homogenizing plate 13, one part of the gas flow is parallel to laminar flow along the gas flow baffle 24, the other part of the gas flow flows along the back surface of the gas flow homogenizing plate 13, the upper surface of the view field baffle body 11 and the back surface of the gas flow guide plate 14, and the two latter parts of gas flows are converged, so that the gas outlet flow state is in a laminar flow state, and finally the gas flows out from the view field window 12. The anti-pollution protection device is arranged on the optical glass, and a protective air layer capable of resisting lateral disturbance can be formed on the surface of the optical glass to be protected.

Specifically, the gap between the air flow baffle 24 and the air flow homogenizing plate 13 is set to 0.5mm to 2mm. Preferably, the gap between the air flow baffle 24 and the air flow homogenizing plate 13 needs to be set within 1mm-1.5mm to ensure a sufficiently uniform distribution of the outlet air flow rate.

The field of view window 12 may be shaped differently depending on the optical design requirements. In some application scenarios, as shown in fig. 7, the field of view window 12 is square in shape. In other applications, as shown in FIG. 8, the field of view window 12 is rectangular in shape. The field window 12 is adapted to the outgoing line of the optical glass without shielding.

Further, as shown in fig. 2, the outer annular wall of the second annular channel 23 is provided with a first dust removing hole 3 therethrough. Further, as shown in fig. 9, the first annular passage 22 is provided with the second dust removing hole 4. In the use process of the anti-pollution protection device, the first powder cleaning hole 3 and the second powder cleaning hole 4 are both in a blocked state. After the anti-pollution protection device is used for a certain time, the air gun is communicated with the first powder cleaning hole 3 and the second powder cleaning hole 4 to blow air, and sediment or dust in the anti-pollution protection device is thoroughly blown out to finish cleaning work.

Specifically, the second annular channel 23 is provided with a first powder cleaning hole 3, and two second powder cleaning holes 4 arranged at intervals are arranged below the first annular channel 22.

Further, as shown in fig. 2 and 9, the first annular channel 22 is provided with a first mounting hole 5, the viewing baffle body 11 is provided with a second mounting hole 6, the first mounting hole 5 is disposed corresponding to the second mounting hole 6, and the viewing baffle body 11 is connected to the first mounting hole 5 by a fastener. Specifically, the first mounting hole 5 is a screw hole. The first mounting holes 5 are provided in plurality. Specifically, the first mounting holes 5 are provided in four, and the four first mounting holes 5 are provided at even intervals below the first annular passage 22.

Further, as shown in fig. 9, the first mounting hole 5 and the second dust removing hole 4 are located on the same side of the first annular passage 22. As shown in fig. 2, the view field baffle body 11 is convexly provided with a blocking head 7, and the blocking head 7 is correspondingly arranged with the second powder cleaning hole 4. When the view field baffle body 11 is arranged on the annular main body structure 2, the blocking head 7 is in sealing connection with the second powder cleaning hole 4.

The embodiment also provides an objective lens, including objective lens and the above-mentioned anti-pollution protection device, the objective lens sets up in annular main body structure 2 one side of keeping away from visual field baffle 1, and the objective lens sets up with visual field window 12 is coaxial, avoids sheltering from light, through holding the abundant homogenization that forms in the chamber 21 and can anti side disturbance's protective gas layer, improves the cleanliness factor on objective lens surface.

The embodiment also provides a photoetching machine, which comprises the anti-pollution protection device, wherein the view field window 12 is a rectangular opening, and the anti-pollution protection device is detachably connected with the objective lens.

The principle of the present apparatus is that Clean Dry Gas (CDA) is first flowed into the second annular channel 23 from the Gas inlet 231, and the flow direction is changed and uniformly distributed in the flow channel, and the uniform flow rate of the Gas is generated by the non-uniform pore diameter distribution of the plurality of communication holes 232, and flows into the first annular channel 22. The first annular channel 22 further homogenizes the exit flow rate through the non-uniformly pore size distribution nozzle 221 and the flow homogenizing plate 13. The outlet flow rate is ensured, and the outlet flow rate of the optimized nozzle 221 should be maintained within the range of 0.7m/s-1m/s, and the number of internal holes and the inlet flow rate are set within this range. The design of the second annular channel 23, the first annular channel 22 and the air flow homogenizing plate 13 in a mutually matched mode ensures the uniform distribution of the air outlet flow velocity to the maximum extent on the basis of ensuring the air outlet flow velocity, and ensures that the air outlet flow state is in a laminar flow state, thereby forming an air protection layer resistant to lateral disturbance. Meanwhile, positive pressure gas is generated in the accommodating cavity 21, so that pollutants are difficult to enter the device, and under the condition of lateral disturbance, the semi-closed accommodating cavity 21 is a design theoretical basis for effectively keeping the pollution-proof performance of the device (the surface pollution degree of the optical glass is kept below 0.5%).

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

1. An anti-pollution protection device, comprising:

the annular main body structure (2) comprises a containing cavity (21), a first annular channel (22) and a second annular channel (23) which are sequentially arranged from inside to outside, wherein an air inlet (231) is formed in the outer wall of the second annular channel (23) in a penetrating mode, the second annular channel (23) is communicated with the first annular channel (22), the first annular channel (22) is communicated with the containing cavity (21), and the containing cavity (21) is communicated with the annular main body structure (2) along the axial direction of the first annular channel (22);

the view field baffle (1) is arranged in the accommodating cavity (21) and is connected with the annular main body structure (2), the view field baffle (1) comprises a view field baffle body (11), a view field window (12) is formed in the view field baffle body (11), and the view field window (12) penetrates through the view field baffle body (11) along the axial direction of the first annular channel (22).

2. The anti-pollution protection device according to claim 1, wherein a plurality of communication holes (232) are circumferentially arranged on the second annular channel (23) at intervals, and the second annular channel (23) is communicated with the first annular channel (22) through the communication holes (232).

3. The pollution protection device according to claim 2, wherein the communication hole (232) is arranged non-coaxially with the air inlet (231).

4. The pollution prevention apparatus according to claim 1, wherein a plurality of nozzles (221) are circumferentially arranged on the first annular channel (22) at intervals, and the first annular channel (22) communicates with the accommodation chamber (21) through the nozzles (221).

5. The anti-pollution protection device according to claim 4, wherein the view field baffle (1) further comprises an air flow homogenizing plate (13), the air flow homogenizing plate (13) is annularly arranged on the view field baffle body (11), the air flow homogenizing plate (13) is arranged at a first preset included angle B with the view field baffle body (11), and the height of the upper end face of the air flow homogenizing plate (13) is not less than the height of the nozzle (221).

6. The anti-pollution protection device according to claim 5, characterized in that the angle between the air flow homogenizing plate (13) and the view-field baffle body (11) is a rounded or sharp angle.

7. The anti-pollution protection device according to claim 5, characterized in that an air flow baffle (24) extending towards the center is circumferentially arranged on the annular main body structure (2) at the side of the nozzle (221) away from the view field baffle (1), and a gap exists between the lower end surface of the air flow baffle (24) and the upper end surface of the air flow homogenizing plate (13).

8. The anti-pollution protection device according to claim 5 or 7, wherein the field baffle (1) further comprises an airflow deflector (14), the airflow deflector (14) is annularly arranged on the field baffle body (11), the airflow deflector (14) is arranged at a second preset included angle C with the field baffle body (11), and the height of the airflow deflector (14) is smaller than the height of the airflow homogenizing plate (13).

9. The contamination protection arrangement according to claim 8, wherein the air flow homogenizing plate (13) extends obliquely in a direction approaching the nozzle (221) and the first preset angle B between the air flow homogenizing plate (13) and the field stop body (11) is 25 ° -85 °.

10. The anti-pollution protection device according to claim 8, wherein the air flow deflector (14) extends obliquely in a direction away from the nozzle (221), and the second preset angle C between the air flow deflector (14) and the field stop body (11) is 25 ° -40 °.

11. The anti-pollution protection device according to claim 1, characterized in that the outer annular wall of the second annular channel (23) is provided with a first dust removal hole (3) therethrough, and the first annular channel (22) is provided with a second dust removal hole (4).

12. The pollution protection device according to claim 2, wherein the air inlet (231) extends in a radial direction of the second annular channel (23).

13. An objective lens, characterized by comprising an objective lens and an anti-pollution protection device according to any one of claims 1-12, wherein the objective lens is arranged on the side of the annular main body structure (2) away from the field stop plate (1), and the objective lens is coaxially arranged with the field window (12).

14. A lithographic apparatus comprising the objective of claim 13.