Objective lens protection device and working method thereof, and photolithography machine

Abstract

The present invention discloses an objective lens protection device and a working method thereof, and a photolithography machine. An intermediate connecting plate in the objective lens protection device is arranged opposite to the lens mirror surface of the objective lens to be protected, and the intermediate connecting plate includes an air outlet, which penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens mirror surface; a first annular air cavity includes a first air inlet and a first air outlet filter, the first air inlet is arranged on the side wall of the first annular air cavity away from the intermediate connecting plate, and the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals; a second annular air cavity includes a second air inlet and a second air outlet filter, the second air inlet is arranged on the side wall of the second annular air cavity away from the intermediate connecting plate, and the second air outlet filter is arranged opposite to the surface of the lens barrel of the objective lens to be protected on the side close to the objective lens protection device and at equal intervals. The technical solution provided by the embodiment of the present invention avoids contamination of the objective lens.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of photolithography technology, and in particular to an objective lens protection device and a working method thereof, and a photolithography machine. Background Art

[0002] The objective lens in the lithography machine is used to reduce the pattern on the mask according to a certain ratio and map it onto a silicon wafer coated with photoresist. At the same time, it performs optical error compensation in the above process. It is an important component of the lithography machine and has a great impact on the lithography accuracy.

[0003] In the prior art, a bottom flow plate is arranged between the objective lens and the silicon wafer, and the bottom flow plate can form an air curtain between the light-collecting area of ​​the objective lens and the silicon wafer to prevent the gas and particles generated by the photoresist exposure from polluting the objective lens. However, the air curtain is formed by pumping, and a negative pressure environment is formed near the pumping area, resulting in a poor sealing of the air curtain. After the photoresist is exposed for a period of time, harmful gases and particles will still pass through the air curtain and pollute the objective lens. Summary of the invention

[0004] The invention provides an objective lens protection device and a working method thereof, and a photolithography machine, so as to prevent the objective lens from being contaminated.

[0005] In a first aspect, an embodiment of the present invention provides an objective lens protection device, comprising a protection device body, wherein the protection device body comprises an intermediate connecting plate and a first annular air cavity and a second annular air cavity sequentially arranged around the intermediate connecting plate;

[0006] Wherein, the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, and the intermediate connecting plate comprises an air outlet, and the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface;

[0007] The first annular air cavity comprises a first air inlet hole and a first air outlet filter, wherein the first air inlet hole is arranged on a side wall of the first annular air cavity away from the middle connecting plate, and the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals;

[0008] The second annular air cavity includes a second air inlet hole and a second air outlet filter. The second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate. The second air outlet filter is opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and is arranged at equal intervals.

[0009] In a second aspect, an embodiment of the present invention further provides a lithography machine, comprising the objective lens protection device described in the first aspect.

[0010] In a third aspect, an embodiment of the present invention further provides a working method of an objective lens protection device, which is performed using the objective lens protection device described in the first aspect. The working method of the objective lens protection device includes:

[0011] The protective device body of the objective lens protective device is fixed so that the middle connecting plate of the objective lens protective device is arranged opposite to the lens surface of the objective lens to be protected, the light-collecting area of ​​the lens surface is exposed from the air outlet on the middle connecting plate, the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at an equal interval, and the second air outlet filter is arranged opposite to the surface of the lens barrel of the objective lens to be protected on the side close to the objective lens protective device and at an equal interval;

[0012] A first gas is input into the first annular air cavity through the first air inlet hole, and a second gas is input into the second annular air cavity through the second air inlet hole. The flow rate of the first gas is smaller than the flow rate of the second gas, and the density of the first gas is different from the density of the second gas.

[0013] The objective lens protection device provided by the embodiment of the present invention comprises a protective device body including an intermediate connecting plate and a first annular air cavity and a second annular air cavity sequentially arranged around the intermediate connecting plate, wherein the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, the intermediate connecting plate comprises an air outlet, the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface, the first annular air cavity comprises a first air inlet and a first air outlet filter, the first air inlet is arranged on the side wall of the first annular air cavity away from the intermediate connecting plate, the first air outlet filter is opposite to the lens side wall of the objective lens to be protected and The second annular air cavity is arranged at equal intervals, and includes a second air inlet hole and a second air outlet filter. The second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate. The second air outlet filter is opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and is arranged at equal intervals, thereby forming a stable positive pressure area between the objective lens to be protected and the objective lens protection device, ensuring that the gas and particulate contaminants generated by photoresist exposure cannot flow into the positive pressure area, and cannot further reach the lens of the objective lens to be protected, thereby avoiding contamination of the objective lens to be protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0015] Figure 1 It is a partial structural schematic diagram of the exposure process in the prior art;

[0016] Figure 2 is a schematic diagram of the positional relationship between the objective lens and the objective lens protection device provided by an embodiment of the present invention;

[0017] Figure 3is along Figure 2 A cross-sectional view of the middle dashed line BB;

[0018] Figure 4 is along Figure 2 Cross-sectional view of the middle dashed line CC;

[0019] Figure 5 It is a schematic diagram of the positional relationship between another objective lens and an objective lens protection device provided by an embodiment of the present invention;

[0020] Figure 6 is along Figure 5 A schematic diagram of the cross-sectional structure of the middle dotted line BB;

[0021] Figure 7 is along Figure 5 The cross-sectional structure diagram of the middle dotted line CC;

[0022] Figure 8 It is a schematic diagram of the positional relationship between another objective lens and an objective lens protection device provided by an embodiment of the present invention;

[0023] Fig. 9 is along Figure 8 A cross-sectional view of the middle dashed line BB;

[0024] Fig.10 is along Figure 8 Cross-sectional view of the middle dashed line CC;

[0025] Fig.11 It is a flow chart of a working method of an objective lens protection device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following, in combination with the accompanying drawings and preferred embodiments, a lens protection device and its working method, a specific implementation method, structure, characteristics and effects of a photolithography machine proposed according to the present invention are described in detail as follows.

[0027] An embodiment of the present invention provides an objective lens protection device, comprising a protection device body, wherein the protection device body comprises an intermediate connecting plate and a first annular air cavity and a second annular air cavity sequentially arranged around the intermediate connecting plate;

[0028] Wherein, the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, and the intermediate connecting plate comprises an air outlet, and the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface;

[0029] The first annular air cavity comprises a first air inlet hole and a first air outlet filter, wherein the first air inlet hole is arranged on a side wall of the first annular air cavity away from the middle connecting plate, and the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals;

[0030] The second annular air cavity includes a second air inlet hole and a second air outlet filter. The second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate. The second air outlet filter is opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and is arranged at equal intervals.

[0031] The objective lens protection device provided by the embodiment of the present invention comprises a protective device body including an intermediate connecting plate and a first annular air cavity and a second annular air cavity sequentially arranged around the intermediate connecting plate, wherein the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, the intermediate connecting plate comprises an air outlet, the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface, the first annular air cavity comprises a first air inlet and a first air outlet filter, the first air inlet is arranged on the side wall of the first annular air cavity away from the intermediate connecting plate, the first air outlet filter is opposite to the lens side wall of the objective lens to be protected and The second annular air cavity is arranged at equal intervals, and includes a second air inlet hole and a second air outlet filter. The second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate. The second air outlet filter is opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and is arranged at equal intervals, thereby forming a stable positive pressure area between the objective lens to be protected and the objective lens protection device, ensuring that the gas and particulate contaminants generated by photoresist exposure cannot flow into the positive pressure area, and cannot further reach the lens of the objective lens to be protected, thereby avoiding contamination of the objective lens to be protected.

[0032] The above is the core idea of ​​the present application. The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented using other embodiments different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams showing the device structure are not partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and height should be included.

[0035] Figure 1 FIG. 1 is a schematic diagram of a part of the structure of the exposure process in the prior art. Figure 1 As shown, a bottom flow plate 30 is arranged between the objective lens 10 and the silicon wafer 20 coated with the photoresist 21. The bottom flow plate 30 forms an air curtain opening 31 corresponding to the lens light-collecting area of ​​the objective lens 10. One end A of the air curtain opening 31 is a gas supply end for providing ultrapure gas, and the other end B is an exhaust end for extracting ultrapure gas output from the gas supply end, thereby forming an air curtain in the air curtain opening 31, which has a blocking effect on polluted air and particles. However, due to the existence of the exhaust negative pressure, the air curtain is not tightly sealed, and the gas and particles generated by the exposure of the photoresist will still pass through the air curtain and pollute the objective lens 10.

[0036] To solve the above problems, an embodiment of the present invention provides an objective lens protection device, which forms a positive pressure environment in the area between the objective lens and the objective lens protection device, thereby ensuring that the gas and particles generated by photoresist exposure will not pass through the area to contaminate the objective lens.

[0037] Specifically, Figure 2 The figure is a schematic diagram of the positional relationship between the objective lens and the objective lens protection device provided by an embodiment of the present invention. Figure 3 is along Figure 2 Cross-sectional view along the dashed line BB. Figure 4 is along Figure 2 The cross-sectional view of the dashed line CC. Figure 2 , Figure 3 and Figure 4 As shown, the objective lens protection device comprises a protection device body 1 , and the protection device body 1 comprises an intermediate connecting plate 100 and a first annular air cavity 200 and a second annular air cavity 300 which are sequentially arranged around the intermediate connecting plate 100 .

[0038] The intermediate connecting plate 100 is disposed opposite to the lens surface 11 of the objective lens 10 to be protected. The intermediate connecting plate 100 includes an air outlet 110 , which penetrates the intermediate connecting plate 100 to expose the light-collecting area of ​​the lens surface 11 .

[0039] The first annular air cavity 200 includes a first air inlet hole 210 and a first air outlet filter 220. The first air inlet hole 210 is arranged on the side wall of the first annular air cavity 200 away from the intermediate connecting plate 100. The first air outlet filter 220 is arranged opposite to the lens side wall 13 of the objective lens 10 to be protected and at equal intervals. The second annular air cavity 300 includes a second air inlet hole 310 and a second air outlet filter 320. The second air inlet hole 310 is arranged on the side wall of the second annular air cavity 300 away from the intermediate connecting plate 100. The second air outlet filter 320 is arranged opposite to the surface 14 of the lens barrel of the objective lens 10 to be protected on the side close to the objective lens protection device and at equal intervals.

[0040] The lens mirror surface 11 of the objective lens 10 to be protected is the surface of the lens opposite to the silicon wafer coated with photoresist, and the light-collecting area of ​​the lens mirror surface 11 is the area where light passes through the lens mirror surface 11. It can be understood that the size of the air outlet 110 is larger than the size of the light-collecting area to avoid blocking the light transmitted in the objective lens 10 to be protected, thereby affecting the exposure quality. Exemplarily, the diameter of the air outlet 110 can be 50 mm.

[0041] During the exposure process, a first gas with a first density and a first flow rate is input from the first air inlet 210 to the first annular air cavity 200, and the first gas in the first annular air cavity 200 is output to the area between the objective lens to be protected 10 and the protection device body 1 through the first air outlet filter 220, and a second gas with a second density and a second flow rate is input from the second air inlet 310 to the second annular air cavity 300, and the second gas in the second annular air cavity 300 is output to the area between the objective lens to be protected 10 and the protection device body 1 through the second air outlet filter 320. Preferably, the first density is different from the second density, and the first flow rate is less than the second flow rate. In this way, two gases with density difference form two layers of circulation, and the second gas with large flow rate and located on the upper side can block the first gas from flowing to the side away from the gas outlet 110, and the diffusion speed between gases with different densities is slow, so that almost all of the first gas flows out from the gas outlet 110, and the gas flow direction between the lens mirror surface 11 of the objective lens 10 to be protected and the silicon wafer is single, and the harmful gases and particles generated by the photoresist on the upper surface of the silicon wafer cannot reach the lens mirror surface 11 of the objective lens 10 to be protected, thereby avoiding contamination of the objective lens 10 to be protected and better protecting the objective lens 10 to be protected. It can be understood that the greater the density difference between the two gases, the slower the diffusion speed between the two, and the better the protection effect on the objective lens 10 to be protected.

[0042] It is understandable that both the first air outlet filter 220 and the second air outlet filter 320 are mesh structures, including a plurality of meshes, which is conducive to improving the stability of the area between the objective lens 10 to be protected and the protection device body 1. Preferably, the first air outlet filter includes a plurality of first meshes, the plurality of first meshes are evenly distributed, and the second air outlet filter includes a plurality of second meshes, the plurality of second meshes are evenly distributed, so as to further improve the stability of the above-mentioned area.

[0043] For example, in actual use, the distance between the objective lens 10 to be protected and the silicon wafer coated with photoresist is 8 mm, the distance between the lower surface of the objective lens protection device and the silicon wafer coated with photoresist is in the range of 1 to 3 mm, and the distance between the second air outlet filter 220 and the surface 14 of the lens barrel of the objective lens 10 to be protected close to the objective lens protection device is in the range of 3 to 10 mm.

[0044] Optional, such as Figure 3 and Figure 4 As shown, the number of the first air inlet holes 210 and the number of the second air inlet holes 310 can both be four and evenly distributed, thus ensuring the uniformity of the airflow.

[0045] The objective lens protection device provided in the present embodiment includes a protection device body comprising an intermediate connecting plate and a first annular air cavity and a second annular air cavity sequentially arranged around the intermediate connecting plate, wherein the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, the intermediate connecting plate includes an air outlet, the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface, the first annular air cavity includes a first air inlet and a first air outlet filter, the first air inlet is arranged on the side wall of the first annular air cavity away from the intermediate connecting plate, the first air outlet filter is opposite to and equal to the side wall of the lens of the objective lens to be protected The second annular air cavity comprises a second air inlet hole and a second air outlet filter, the second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate, and the second air outlet filter is arranged opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and at equal intervals, thereby forming a stable positive pressure area between the objective lens to be protected and the objective lens protection device, ensuring that the gas and particulate contaminants generated by the exposure of the photoresist cannot flow into the positive pressure area, and cannot further reach the lens of the objective lens to be protected, thereby avoiding contamination of the objective lens to be protected.

[0046] Figure 5 The figure is a schematic diagram of the positional relationship between another objective lens and an objective lens protection device provided by an embodiment of the present invention. Figure 6 is along Figure 5 Schematic diagram of the cross-sectional structure of the dotted line BB. Figure 7 is along Figure 5 The cross-sectional structure diagram of the dashed line CC is shown in FIG. Figure 5 , Figure 6 and Figure 7As shown, the protection device body 1 further includes a pumping cavity 400 , which is arranged around the first annular air cavity 200 and is located on a side of the second annular air cavity 300 away from the objective lens 10 to be protected.

[0047] It should be noted that the harmful gases and particles generated by the photoresist during exposure move from the surface of the silicon wafer to the side of the objective lens 10 to be protected. Affected by the airflow in the air outlet 110, the harmful gases and particles will move in the opposite direction, which may easily cause silicon wafer contamination. To avoid the above problems, the present embodiment provides an exhaust chamber 400 for absorbing the harmful gases and particles generated by the photoresist during exposure to prevent the harmful gases and particles from falling back to the surface of the silicon wafer. In addition, the exhaust chamber 400 is provided on the side of the protective device body 1 close to the silicon wafer, so that the influence of the exhaust chamber 400 on the pressure distribution in the area between the objective lens 10 to be protected and the protective device body 1 can be reduced.

[0048] Continue to see Figure 7 The pumping chamber may include four sub-pumping chambers 410, and the four sub-pumping chambers 410 are arranged in sequence with equal intervals.

[0049] It should be noted that, compared with a single extraction chamber, in the structure including four sub-extraction chambers 410, the power required to achieve the same extraction force is smaller, and the uniformity of the extraction force is better, which is conducive to the effective extraction of harmful gases and particulate matter in various areas of the silicon wafer surface.

[0050] Figure 8 The figure is a schematic diagram of the positional relationship between another objective lens and an objective lens protection device provided by an embodiment of the present invention. Fig. 9 is along Figure 8 Cross-sectional view along the dashed line BB. Fig.10 is along Figure 8 The cross-sectional view of the dashed line CC. Figure 8 , Fig. 9 and Fig.10 As shown, the objective lens protection device may further include a plurality of voice coil motors 500 , which are connected to the protection device body 1 and are used to control the protection device body 1 to move toward or away from the objective lens 10 to be protected.

[0051] It should be noted that the objective lens 10 to be protected, the protection device body 1 and the plurality of voice coil motors 500 are all mounted on the main substrate 2. Figure 8 , Fig. 9 and Fig.10 shown.

[0052] It should also be noted that the multiple voice coil motors 500 are respectively connected to different positions of the protection device body 1. Compared with a single voice coil motor 500, the multiple voice coil motors 500 can make more contact points on the protection device body 1, and the stability of the protection device body 1 is better when moving.

[0053] It can be understood that the up and down movement of the protection device body 1 can adjust the gap width between the objective lens 10 to be protected and the protection device body 1, and then adjust the overpressure of the air outlet 110 to ensure that the pressure in the area between the objective lens 10 to be protected and the protection device body 1 is moderate, which can prevent harmful gases and particles from passing through without damaging the silicon wafer and the objective lens 10 to be protected.

[0054] Continue to see Figure 8 , Fig. 9 and Fig.10 The objective lens protection device may further include an absolute pressure sensor 600, and the absolute pressure sensor 600 is used to detect the bottom pressure of the objective lens 10 to be protected.

[0055] In this way, the absolute pressure sensor 600 can transmit the detected bottom pressure of the objective lens 10 to be protected to the control system. The control system controls the voice coil motor 500 to adjust the movement of the protection device body 1 to a corresponding distance based on the received bottom pressure. The two cooperate to adjust the pressure in the area between the objective lens 10 to be protected and the protection device body 1.

[0056] For example, Figure 8 The structure shown in the figure is simulated under the following simulation conditions: the flow rate of the second gas is helium, and its flow rate is 16.8L / min, the first gas is ultrapure compressed dry gas, and its flow rate is 8.37L / min, and the pressure of the gas outlet 110 is 0Pa. The simulation results are as follows: the gas output from the gas outlet 110 includes 40% of the second gas and 60% of the first gas, and the gas output from the outlet between the protection device body 1 and the surface 14 of the lens barrel of the objective lens 10 to be protected close to the objective lens protection device includes 80% of the second gas and 20% of the first gas, and the overpressure at 3mm below the lens mirror surface 14 of the objective lens 10 to be protected is 0.063Pa. Specifically, when the diameter of the gas outlet 110 is 50mm, and the overpressure at 3mm below the lens mirror surface 14 of the objective lens 10 to be protected is 0.063Pa, the pressure on the silicon wafer is calculated to be 0.12mN, which is small and will not cause damage to the silicon wafer. It should be noted that this is a simulation based on a stable state, and the results obtained are the results under a stable state.

[0057] Furthermore, in order to analyze the influence of the density of the mixed gas on the optical path, the density and its standard deviation at 6 positions in the area between the protection device body 1 and the objective lens 10 to be protected were statistically analyzed, as shown in Table 1. It can be seen that the maximum value of the standard deviation of the density at the same height is 3.66%, and it can also be calculated that the standard deviation of the density at different heights is 0.36%. It can be seen that the density of the mixed gas at different positions in the area between the protection device body 1 and the objective lens 10 to be protected is not much different, which has little effect on the propagation path of the light and will not affect the lithography accuracy.

[0058] Table 1

[0059] Location Density mean Standard Deviation Standard Deviation Percentage 0 0.7448 0.014 1.88％ 1 0.7551 0.0261 3.46％ 2 0.755 0.0263 3.48％ 3 0.7545 0.0266 3.53％ 4 0.7539 0.027 3.58％ 5 0.7537 0.0276 3.66％

[0060] Fig.11 1 is a flow chart of a working method of an objective lens protection device provided by an embodiment of the present invention. The working method of the objective lens protection device is performed by using the objective lens protection device provided by any embodiment of the present invention, such as Fig.11 As shown, the working method of the objective lens protection device may specifically include the following:

[0061] Step 11, fix the protection device body of the objective lens protection device so that the middle connecting plate of the objective lens protection device is arranged opposite to the lens mirror surface of the objective lens to be protected, the light-collecting area of ​​the lens mirror surface is exposed from the air outlet on the middle connecting plate, the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals, and the second air outlet filter is arranged opposite to the surface of the lens of the objective lens to be protected close to the lens side and at equal intervals.

[0062] Step 12: Input a first gas into the first annular air cavity through the first air inlet hole, and input a second gas into the second annular air cavity through the second air inlet hole. The flow rate of the first gas is smaller than the flow rate of the second gas, and the density of the first gas is different from the density of the second gas.

[0063] The technical solution provided in this embodiment is to fix the protection device body of the objective lens protection device so that the middle connecting plate of the objective lens protection device is arranged opposite to the lens mirror surface of the objective lens to be protected, and the light-collecting area of ​​the lens mirror surface is exposed from the air outlet on the middle connecting plate, the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals, the second air outlet filter is arranged opposite to the surface of the lens of the objective lens to be protected close to the lens side and at equal intervals, and the first gas is input into the first annular air cavity through the first air inlet hole, and the second gas is input into the second annular air cavity through the second air inlet hole, the flow rate of the first gas is less than the flow rate of the second gas, and the density of the first gas is different from the density of the second gas, so as to form a stable positive pressure area between the objective lens to be protected and the objective lens protection device, thereby ensuring that the gas and particulate contaminants generated by photoresist exposure cannot flow into the positive pressure area, and cannot further reach the lens of the objective lens to be protected, thereby avoiding contamination of the objective lens to be protected.

[0064] Optionally, before the first gas is input into the first annular air cavity through the first air inlet hole and the second gas is input into the second annular air cavity through the second air inlet hole, the method may further include: controlling the exhaust cavity to exhaust gas.

[0065] Exemplarily, the first gas is ultrapure compressed dry gas, nitrogen or carbon dioxide gas, and the second gas is helium; alternatively, the first gas is carbon dioxide gas and the second gas is nitrogen; alternatively, the first gas is carbon dioxide gas and the second gas is ultrapure compressed dry gas.

[0066] It should be noted that the above gas combination is only used as an example for illustration and is not limiting. In other implementations of this embodiment, the first gas and the second gas may also be in other combinations.

[0067] In this embodiment, before the first gas is input into the first annular air cavity through the first air inlet hole and the second gas is input into the second annular air cavity through the second air inlet hole, the method may further include: a control system controls the plurality of voice coil motors to adjust the position of the protection device body.

[0068] Optionally, before adjusting the position of the protection device body by using a plurality of voice coil motors, the method may further include: detecting the bottom pressure of the objective lens to be protected by using an absolute pressure sensor, and transmitting the detected bottom pressure to a control system.

[0069] Among them, the control system can be a flow control system, and the flow control system can be, for example, an inherent flow control system in the lithography machine. In this way, there is no need to specially set up a control system for controlling the flow of the first gas and the second gas, which is conducive to the simplification of the lithography machine structure.

[0070] Note that the above are only preferred embodiments of the present invention and the technical principles used. 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, combinations 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 more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An objective lens protection device, characterized in that: The protective device comprises a protective device body, wherein the protective device body comprises an intermediate connecting plate and a first annular air cavity and a second annular air cavity which are sequentially arranged around the intermediate connecting plate; Wherein, the intermediate connecting plate is arranged opposite to the lens surface of the objective lens to be protected, and the intermediate connecting plate comprises an air outlet, and the air outlet penetrates the intermediate connecting plate to expose the light-collecting area of ​​the lens surface; The first annular air cavity comprises a first air inlet hole and a first air outlet filter, wherein the first air inlet hole is arranged on a side wall of the first annular air cavity away from the middle connecting plate, and the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at equal intervals; The second annular air cavity includes a second air inlet hole and a second air outlet filter. The second air inlet hole is arranged on the side wall of the second annular air cavity away from the middle connecting plate. The second air outlet filter is opposite to the surface of the lens barrel of the objective lens to be protected close to the objective lens protection device and is arranged at equal intervals.

2. The objective lens protection device according to claim 1, characterized in that: The protection device body also includes a pumping cavity, which is arranged around the first annular air cavity and is located on a side of the second annular air cavity away from the objective lens to be protected.

3. The objective lens protection device according to claim 2, characterized in that: The pumping chamber includes four sub-pumping chambers, and the four sub-pumping chambers are arranged in sequence with equal intervals.

4. The objective lens protection device according to claim 1, characterized in that: It also includes a plurality of voice coil motors, which are connected to the protection device body and are used to control the protection device body to move toward or away from the objective lens to be protected.

5. The objective lens protection device according to claim 4, characterized in that: It also includes an absolute pressure sensor, which is used to detect the bottom pressure of the objective lens to be protected.

6. A photolithography machine, characterized in that: The objective lens protection device comprises the objective lens protection device according to any one of claims 1 to 5.

7. A method for operating an objective lens protection device, implemented by using the objective lens protection device according to any one of claims 1 to 5, characterized in that: include: The protective device body of the objective lens protective device is fixed so that the middle connecting plate of the objective lens protective device is arranged opposite to the lens mirror surface of the objective lens to be protected, the light-collecting area of ​​the lens mirror surface is exposed from the air outlet on the middle connecting plate, the first air outlet filter is arranged opposite to the lens side wall of the objective lens to be protected and at an equal interval, and the second air outlet filter is arranged opposite to the surface of the lens of the objective lens to be protected close to the lens side and at an equal interval; A first gas is input into the first annular air cavity through the first air inlet hole, and a second gas is input into the second annular air cavity through the second air inlet hole. The flow rate of the first gas is smaller than the flow rate of the second gas, and the density of the first gas is different from the density of the second gas.

8. The working method according to claim 7, characterized in that: Before the first gas is input into the first annular air cavity through the first gas inlet hole and the second gas is input into the second annular air cavity through the second gas inlet hole, the method further includes: Control the exhaust chamber to exhaust air.

9. The working method according to claim 7, characterized in that: The first gas is ultrapure compressed dry gas, nitrogen or carbon dioxide gas, and the second gas is helium; or, the first gas is carbon dioxide gas and the second gas is nitrogen; or, the first gas is carbon dioxide gas and the second gas is ultrapure compressed dry gas.

10. The working method according to claim 7, characterized in that: Before the first gas is input into the first annular air cavity through the first gas inlet hole and the second gas is input into the second annular air cavity through the second gas inlet hole, the method further includes: The control system controls a plurality of voice coil motors to adjust the position of the protection device body.

11. The working method according to claim 10, characterized in that: Before adjusting the position of the protection device body by using a plurality of voice coil motors, the method further includes: The bottom pressure of the objective lens to be protected is detected by an absolute pressure sensor, and the detected bottom pressure is transmitted to the control system.

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