Objective lens gas leakage detection method, objective lens and photolithography machine

Abstract

The present application provides an objective lens gas leakage detection method, an objective lens and a photolithography machine, and belongs to the field of imaging equipment technology. The gas leakage detection method includes: obtaining the internal oxygen concentration value of an optical spacer cavity in a first sensitivity interval, and controlling whether an air inlet is inhaled and the air inlet parameters of the air inlet when inhaling based on the obtained oxygen concentration value; the air inlet parameters of the air inlet include the air intake volume and / or air intake pressure and / or air intake duration of the air inlet. In the present application, by obtaining the internal oxygen concentration value of the optical spacer cavity at the strongest position in the sensitivity interval of the objective lens, the purity of the process gas inside the objective lens can be determined according to the oxygen concentration value, so that the process gas is adaptively filled into the interior of the objective lens, thereby ensuring the purity of the process gas inside the objective lens, and then ensuring the imaging effect and service life of the objective lens.

Description

Technical Field

[0001] The present application relates to the technical field of imaging equipment, and in particular to a method for detecting gas leakage of an objective lens, an objective lens and a photolithography machine. Background Art

[0002] The performance and quality of the objective lens have a decisive influence on the clarity, resolution and service life of the image.

[0003] In the production process of objective lenses, the purity of internal process gases is a key parameter. Low-purity process gases may cause defects on the lens surface, uneven coating or bubbles, thus affecting the image quality. At the same time, low-purity gases may also accelerate the oxidation and corrosion of the internal structure of the lens, shortening the service life of the objective lens; it directly affects the surface coating of the objective lens, the internal structure of the lens and the overall optical performance. Summary of the invention

[0004] In order to overcome the problems of poor imaging quality and short service life of the objective lens caused by insufficient process gas inside the objective lens in the prior art, an objective lens gas leakage detection method, an objective lens and a photolithography machine are provided in the embodiments of the present application, which can determine the purity of the process gas inside the objective lens according to the oxygen concentration value by obtaining the oxygen concentration value inside the optical spacer cavity at the strongest position in the sensitivity range of the objective lens, so as to adaptively fill the process gas into the objective lens, thereby ensuring the purity of the process gas inside the objective lens, and then ensuring the imaging effect and service life of the objective lens. Specifically:

[0005] In a first aspect, an embodiment of the present application provides a method for detecting gas leakage of an objective lens, wherein a plurality of optical spacing cavities are defined inside the objective lens, the plurality of optical spacing cavities are interconnected to form a gas containing cavity for containing gas, the gas containing cavity has an air inlet, and the air inlet is used to inject process gas into the gas containing cavity, wherein the plurality of optical spacing cavities include an optical spacing cavity of a first sensitivity level in a first sensitivity interval, an optical spacing cavity of a second sensitivity level in a second sensitivity interval... and an optical spacing cavity of an Mth sensitivity level in an Mth sensitivity interval based on a distribution rule of sensitivity from strong to weak;

[0006] Gas leak detection methods include:

[0007] Acquire an internal oxygen concentration value of the optical spacer cavity in a first sensitivity interval, and control whether the air inlet is to be inhaled and the air inlet parameters of the air inlet when inhaling air based on the acquired oxygen concentration value;

[0008] The air intake parameters of the air intake port include the air intake volume and / or the air intake pressure and / or the air intake duration of the air intake port.

[0009] In the above technical solution, the first sensitivity interval contains at least one optical spacing cavity at the first sensitivity level; wherein when the first sensitivity interval contains a plurality of optical spacing cavities at the first sensitivity level;

[0010] Obtaining an internal oxygen concentration value of the optical compartment cavity within a first sensitivity interval, comprising:

[0011] The sensitivity intensities of the plurality of optical compartments in the first sensitivity interval are compared, the optical compartment with the strongest sensitivity is determined based on the comparison result, and the oxygen concentration value in the optical compartment with the strongest sensitivity is obtained.

[0012] In the above technical solution, the internal oxygen concentration value of the optical spacer cavity in the first sensitivity range is obtained, and based on the obtained oxygen concentration value, whether the air inlet is inlet and the air inlet parameters of the air inlet when inletting air are controlled, including:

[0013] Based on the obtained oxygen concentration value, the process gas concentration value in the corresponding optical spacer cavity is calculated, and the opening and closing of the air inlet and the air intake parameters of the air inlet during air intake are controlled according to the process gas concentration.

[0014] In the above technical solution, the internal oxygen concentration value of the optical spacer cavity in the first sensitivity range is obtained, and based on the obtained oxygen concentration value, whether the air inlet is inlet and the air inlet parameters of the air inlet when inletting air are controlled, including:

[0015] Determining whether the oxygen concentration value is greater than a first preset oxygen concentration value;

[0016] If the oxygen concentration value is greater than the first preset oxygen concentration value, the air inlet is controlled to open;

[0017] If the oxygen concentration value is less than or equal to the first preset oxygen concentration value, the air inlet is controlled.

[0018] In the above technical solution, if the oxygen concentration value is greater than the first preset oxygen concentration value, the air inlet is controlled to open, including:

[0019] If the oxygen concentration value is greater than the first preset oxygen concentration value and less than the second preset oxygen concentration value, the air intake is controlled to take in air at a first air intake volume per unit time;

[0020] If the oxygen concentration value is greater than or equal to the second preset oxygen concentration value, the air intake port is controlled to take in air at a second air intake volume per unit time;

[0021] The first intake air volume is smaller than the second intake air volume.

[0022] A second aspect of the embodiments of the present application provides an objective lens, which adopts the gas leakage detection method provided by the first aspect of the embodiments of the present application.

[0023] A second aspect of the embodiment of the present application further provides an objective lens, comprising:

[0024] An objective lens body, wherein a plurality of optical cavities are defined inside the objective lens body, the plurality of optical cavities are interconnected to form a gas containing cavity for containing gas, the gas containing cavity has a gas inlet, wherein the plurality of optical cavities include, based on a distribution rule of sensitivity from strong to weak, an optical cavities of a first sensitivity level in a first sensitivity interval, an optical cavities of a second sensitivity level in a second sensitivity interval... and an optical cavities of an Mth sensitivity level in an Mth sensitivity interval;

[0025] A sensor, the sensor is used to detect the gas inside the optical compartment cavity in a first sensitivity range and output a parameter value representing the oxygen concentration inside the optical compartment cavity;

[0026] The gas inlet injects process gas into the gas containing chamber when the parameter value exceeds the preset parameter value, and stops injecting process gas when the parameter value does not exceed the preset parameter value.

[0027] In the above technical solution, the sensor includes a dissolved oxygen sensor, which is arranged at a position of the optical compartment cavity within a first sensitivity range and is used to monitor the oxygen concentration value inside the optical compartment cavity.

[0028] In the above technical solution, the objective lens has a plurality of lenses arranged in sequence in the axial direction thereof, and an optical spacing cavity is defined between each two adjacent lenses;

[0029] The objective lens also includes an exhaust port connected to the gas containing chamber, and the exhaust port is controlled to be opened when gas is introduced into the gas inlet;

[0030] One of the air inlet and the air outlet is arranged at one end in the axial direction of the objective lens, and the other is arranged at the other end in the axial direction of the objective lens.

[0031] In the above technical solution, the length of the objective lens in its axial direction is designed to be between 1000mm and 1500mm, and the length of the objective lens in its radial direction is designed to be between 500mm and 800mm;

[0032] The objective lens with an axial length of 1000mm-1500mm and a radial length of 500mm-800mm defines 20-30 optical spacing cavities inside.

[0033] A third aspect of an embodiment of the present application provides a lithography machine, which includes the objective lens provided in the second aspect of an embodiment of the present application.

[0034] In the above technical solution, the lithography machine also includes:

[0035] An air control device, wherein an air inlet pipe is connected between the air control device and the air inlet of the objective lens, and an exhaust pipe is connected between the air control device and the exhaust port of the objective lens;

[0036] The gas control device is used to control whether the air inlet is inlet according to the parameter value output by the sensor that represents the oxygen concentration inside the optical spacer cavity.

[0037] In the above technical solution, the lithography machine also includes:

[0038] A flow control module connected to the air intake line, and

[0039] a controller connected between the flow control module and the sensor, and

[0040] An exhaust pipe connected to the exhaust port of the objective lens;

[0041] The controller is used to adjust the flow control module according to the parameter value representing the oxygen concentration output by the sensor, so as to adjust the intake parameters of the air inlet;

[0042] The air intake parameters of the air intake port include the air intake volume and / or the air intake pressure and / or the air intake duration of the air intake port, and the exhaust port is controlled to be opened when the air intake port is taking in air.

[0043] After adopting the above technical solution, the present application has the following beneficial effects compared with the prior art:

[0044] In the embodiment of the present application, by obtaining the oxygen concentration value inside the optical spacer cavity at the strongest position in the sensitivity range of the objective lens, the purity of the process gas inside the objective lens can be determined according to the oxygen concentration value, so that the process gas is adaptively filled into the objective lens, thereby ensuring the purity of the process gas inside the objective lens, and then ensuring the imaging effect and service life of the objective lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a control flow chart of objective lens gas leakage detection in an embodiment of the present application;

[0046] Figure 2 Schematic diagram of the cross-sectional structure of the objective lens in the embodiment of the present application;

[0047] Figure 3 This is a sensitivity analysis diagram of the optical cavity of the objective lens in the embodiment of the present application;

[0048] Figure 4 Schematic diagram of the connection structure of the objective lens in the embodiment of the present application when in use.

[0049] in:

[0050] 100-objective lens body; 10-lens; 20-optical spacer cavity;

[0051] 200-sensor;

[0052] 300-gas control device;

[0053] 400-intake pipe;

[0054] 500-Flow control module;

[0055] 600-controller;

[0056] 700 - Exhaust pipe. DETAILED DESCRIPTION

[0057] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0058] Throughout the specification and claims, the following terms have at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms, but merely provide illustrative examples of the terms.

[0059] In the description of the present invention, the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it may refer to the same embodiment. Similarly, the phrase "in some embodiments" as used herein, when used multiple times, does not necessarily refer to the same embodiment, although it may refer to the same embodiment. As used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or", unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for additional factors not described, unless the context clearly dictates otherwise. The word "exemplary" means "used as an example, instance or illustration" in this article. Any embodiment described herein as "exemplary" is not necessarily interpreted as being superior or superior to other embodiments. The scope of the present invention is limited only by the scope of the appended claims, and any examples set forth in this specification are not intended to be limiting, but only to set forth some of the many possible embodiments of the claimed invention. The various embodiments provided by the present invention should not be interpreted as limiting the scope of protection of the present invention.

[0060] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0061] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0062] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0064] Background

[0065] The performance and quality of the objective lens have a decisive influence on the clarity, resolution and service life of the image.

[0066] In the production process of objective lenses, the purity of internal process gases is a key parameter. Low-purity process gases may cause defects on the lens surface, uneven coating or bubbles, thus affecting the image quality. At the same time, low-purity gases may also accelerate the oxidation and corrosion of the internal structure of the lens, shortening the service life of the objective lens; it directly affects the surface coating of the objective lens, the internal structure of the lens and the overall optical performance.

[0067] Based on this, Figure 1-Figure 4 As shown, the first aspect of the embodiment of the present application provides a method for detecting gas leakage of an objective lens, such as Figure 2 As shown, a plurality of optical spacing cavities 20 are defined inside the objective lens, and the plurality of optical spacing cavities 20 are interconnected to form a gas containing cavity for containing gas, and the gas containing cavity has a gas inlet, and the gas inlet is used to inject process gas into the gas containing cavity, wherein the plurality of optical spacing cavities 20 include a first sensitivity level optical spacing cavity 20 in a first sensitivity interval, a second sensitivity level optical spacing cavity 20 in a second sensitivity interval... and an Mth sensitivity level optical spacing cavity 20 in an Mth sensitivity interval based on a distribution rule of sensitivity from strong to weak;

[0068] like Figure 1 As shown, the gas leakage detection method includes:

[0069] Acquire the internal oxygen concentration value of the optical spacer cavity 20 in the first sensitivity range, and control whether the air inlet is inlet and the air inlet parameters of the air inlet when inletting air based on the acquired oxygen concentration value;

[0070] The air intake parameters of the air intake port include the air intake volume and / or the air intake pressure and / or the air intake duration of the air intake port.

[0071] It should be noted that the objective lens cavity structure is not a sealed container. There is a certain amount of gas leakage, which leads to a certain mass transfer process between it and the external environment. As we all know, the atmospheric composition outside the objective lens does not have an exact ratio, and different molecules have different refractive indices. If the gas composition and content inside the objective lens are unstable, which is manifested in the change of the purity of the process gas inside the objective lens, it will cause the change of the optical refractive index, thereby causing random fluctuations in the optical indicators.

[0072] Based on this, in the embodiment of the present application, by obtaining the oxygen concentration value inside the optical spacing cavity 20 at the strongest position in the sensitivity range of the objective lens, the purity of the process gas inside the objective lens can be determined according to the oxygen concentration value, so that the process gas, for example, dry and pure inert gases such as helium and argon, is adaptively filled into the objective lens; thereby ensuring the purity of the process gas inside the objective lens, and then ensuring the imaging effect and service life of the objective lens.

[0073] It should also be noted that the sensitivity distribution of each optical cavity 20 is obtained by optical simulation in the embodiment of the present application, wherein the optical simulation method is an existing method for detecting the sensitivity of the objective lens optical cavity 20, and the specific detection process of the method is not described in detail in this embodiment.

[0074] It should also be noted that the "first sensitivity interval" mentioned in the embodiments of the present application represents the position interval where the refractive index is most sensitive due to changes in the purity of the gas inside the objective lens.

[0075] It should also be noted that the reason why the concentration value of oxygen in the optical cavity 20 is obtained in the embodiment of the present application is that oxygen is the most sensitive gas to exposure inside the objective lens. Based on this, by obtaining the concentration value of oxygen inside the objective lens, it is possible to promptly determine whether the purity of the process gas inside the objective lens has changed, thereby being able to promptly adjust and compensate the air intake flow of the objective lens. On the one hand, the purity of the process gas in the sensitive parts of the optical cavity 20 can be effectively and promptly monitored. On the other hand, the flow rate of the objective lens filling gas {process gas} can be timely adjusted and compensated through the obtained process gas purity value, which can also improve the stability and effectiveness of the internal and external environmental monitoring of the objective lens and reduce the gas source consumption cost.

[0076] Further, in some embodiments, the first sensitivity interval includes at least one optical spacing cavity 20 at the first sensitivity level; wherein when the first sensitivity interval includes a plurality of optical spacing cavities 20 at the first sensitivity level;

[0077] Obtaining the internal oxygen concentration value of the optical compartment cavity 20 within the first sensitivity interval includes:

[0078] The sensitivity intensities of the plurality of optical compartments 20 in the first sensitivity interval are compared, the optical compartment 20 with the strongest sensitivity is determined based on the comparison result, and the oxygen concentration value in the optical compartment 20 with the strongest sensitivity is obtained.

[0079] That is, each sensitivity interval may include one optical partition cavity 20 at the first sensitivity level, or may include multiple optical partition cavities 20 at the first sensitivity level.

[0080] When each sensitivity interval contains an optical spacer cavity 20 at the first sensitivity level, the position of the optical spacer cavity 20 is the position where the refractive index is most sensitive to the change in the purity of the process gas inside the objective lens. When the oxygen concentration value at this position exceeds the preset value, it means that the concentration of the process gas inside the objective lens is low. At this time, the process gas can be injected into the objective lens in time to improve the purity of the process gas inside the objective lens.

[0081] When each sensitivity interval includes a plurality of optical compartments 20 at the first sensitivity level, the positions of the plurality of optical compartments 20 at the first sensitivity interval can be identified as the positions where the refractive index is most sensitive due to the change in the purity of the process gas inside the objective lens. When it is monitored that the oxygen concentration value inside at least one optical compartment 20 among the plurality of optical compartments 20 exceeds a preset value, it can also be explained that the concentration of the process gas inside the objective lens is reduced. At this time, the process gas can be injected into the objective lens to improve the purity of the process gas inside the objective lens.

[0082] However, it is relatively preferred to correspond each optical cavity 20 in the objective lens to a sensitivity interval, and to monitor the oxygen concentration value of the optical cavity 20 in the interval with the strongest sensitivity, so as to timely reflect the purity change of the process gas inside the objective lens, thereby enabling the process gas to be filled into the objective lens in the most timely and accurate manner.

[0083] Further, in some embodiments, obtaining an internal oxygen concentration value of the optical spacer cavity 20 in the first sensitivity range, and controlling whether the air inlet is inlet and the air inlet parameters of the air inlet when inletting air based on the obtained oxygen concentration value include:

[0084] Based on the obtained oxygen concentration value, the process gas concentration value in the corresponding optical spacer cavity 20 is calculated, and the opening and closing of the air inlet and the air intake parameters of the air inlet during air intake are controlled according to the process gas concentration.

[0085] Specifically, in the embodiment of the present application, after obtaining the oxygen concentration value inside the optical cavity 20, the purity of the process gas inside the optical cavity 20 can be calculated in the following manner. Specifically, the residual air content inside the optical cavity 20 is calculated by the obtained oxygen content, and the process gas purity % inside the optical cavity 20 is calculated to be 1-residual air content%. When the process gas purity is lower than the set value, the flow control module 200 can be adjusted in time through the air inlet on the objective lens to replenish the process gas inside the objective lens {the relationship between the flow control module 500 and the objective lens will be introduced below}.

[0086] In some embodiments, obtaining an internal oxygen concentration value of the optical spacer cavity 20 in the first sensitivity range, and controlling whether the air inlet is inlet and the air inlet parameters of the air inlet when inletting air based on the obtained oxygen concentration value, include:

[0087] Determining whether the oxygen concentration value is greater than a first preset oxygen concentration value;

[0088] If the oxygen concentration value is greater than the first preset oxygen concentration value, the air inlet is controlled to open;

[0089] If the oxygen concentration value is less than or equal to the first preset oxygen concentration value, the air inlet is controlled to be closed.

[0090] That is, when the calculated purity value of the process gas inside the objective lens meets the preset value, the air inlet is closed at this time, and when the calculated purity value of the process gas inside the objective lens does not meet the preset value, the air inlet is opened.

[0091] It is worth noting that the “gas inlet” mentioned in this embodiment is open, which means that the process gas can enter the interior of the objective lens through the gas inlet position, and it is not required that the gas inlet valve must be set at the gas inlet position.

[0092] In some embodiments, if the oxygen concentration value is greater than a first preset oxygen concentration value, controlling the air inlet to open includes:

[0093] If the oxygen concentration value is greater than the first preset oxygen concentration value and less than the second preset oxygen concentration value, it reflects that the purity of the process gas inside the objective lens is low. At this time, the air inlet can be controlled to intake air at the first air intake volume per unit time;

[0094] If the oxygen concentration value is greater than or equal to the second preset oxygen concentration value, it reflects that the purity of the process gas inside the objective lens is very low. At this time, the air inlet can be controlled to intake air at the second air intake volume per unit time;

[0095] The first intake air volume is smaller than the second intake air volume.

[0096] In other words, in the embodiment of the present application, the air intake volume of the air inlet is controlled according to the difference between the process gas purity value and the preset value. The greater the purity of the process gas, the greater the air intake volume. Therefore, the process gas can be adaptively filled into the objective lens according to the purity value of the process gas inside the objective lens, thereby avoiding the consumption of a large amount of process gas and effectively reducing costs.

[0097] It should be noted that in the prior art, in order to effectively control the purity of the process gas inside the objective lens, the following control measures are mainly adopted:

[0098] Method 1: Gas source selection. Choose a high-quality gas source, such as high-purity nitrogen, high-purity argon, etc., to ensure the initial purity of the gas.

[0099] Method 2: Clean and inspect the pipeline regularly to ensure that the inside of the pipeline is clean and free of impurities.

[0100] However, both of the above methods have disadvantages, specifically:

[0101] When the first method is adopted, that is, a high-purity gas source is selected, it can only control the purity of the gas from the source, but cannot guarantee that the gas entering the objective lens is not contaminated.

[0102] When the second method is adopted, the pipeline is cleaned and inspected regularly. However, after the objective lens is assembled for the first time, it will not be disassembled, cleaned and reassembled. The high-purity gas filled in the objective lens cavity also plays the role of renewing and cleaning the residual air. Doing so for a long time will only consume a large amount of process gas, and the cost cannot be controlled; at the same time, the large flow of gas will cause pressure fluctuations inside the objective lens, affecting the refractive index of the lens gap and the depth of focus index.

[0103] In the embodiment of the present application, by obtaining the oxygen concentration value inside the objective lens, it is possible to timely determine whether the purity of the process gas inside the objective lens has changed, so that the air intake flow rate of the objective lens can be adjusted and compensated in time. On the one hand, the purity of the process gas in the sensitive parts of the optical spacing cavity 20 can be effectively monitored. On the other hand, the flow rate of the objective lens filling gas can be timely adjusted and compensated, which can also improve the stability and effectiveness of the internal and external environment monitoring of the objective lens and reduce the gas source consumption cost.

[0104] Compared with the existing gas path purity control scheme, the scheme in this embodiment can effectively monitor and control the stability of the objective lens gas purity and can reduce the gas source consumption cost.

[0105] Compared with the existing method of cleaning through pipelines, the solution in this embodiment does not require disassembly of the objective lens, which is more convenient and can also reduce the gas source consumption cost. At the same time, in the embodiment of the present application, when the process gas is filled into the interior of the objective lens, it is filled adaptively according to the purity of the process gas.

[0106] That is, the above-mentioned control of the air intake volume per unit time at the air inlet according to the purity value of the process gas inside the objective lens, and the air intake volume per unit time at the air inlet can reflect the air intake pressure. The more the air intake volume per unit time, the greater the air intake pressure. The effect that can be obtained is that, when the process gas is filled into the interior of the objective lens in the embodiment of the present application, the air intake pressure will not be too large {because in the embodiment of the present application, by obtaining the oxygen concentration value inside the optical spacing cavity 20 at the most sensitive position, it is possible to timely reflect the change in the purity of the process gas inside the objective lens and replenish the process gas into the objective lens, and the problem that the purity of the process gas of the objective lens has dropped a lot without being discovered will not occur}, that is, when the objective lens in the embodiment of the present application is filled with process gas, the problem of large fluctuations in the internal pressure of the objective lens due to excessive inflation pressure will not occur.

[0107] Furthermore, a second aspect of the embodiments of the present application provides an objective lens, which includes the gas leakage detection method provided in the first aspect of the embodiments of the present application.

[0108] Further, such as Figure 2 As shown, the second aspect of the embodiment of the present application further provides an objective lens, which includes:

[0109] An objective lens body 100, wherein a plurality of optical spacing cavities 20 are defined inside the objective lens body 100, wherein the plurality of optical spacing cavities 20 are interconnected to form a gas containing cavity for containing gas, wherein the gas containing cavity has a gas inlet, wherein the plurality of optical spacing cavities 20 include, based on a distribution rule of sensitivity from strong to weak, an optical spacing cavity 20 of a first sensitivity level in a first sensitivity interval, an optical spacing cavity 20 of a second sensitivity level in a second sensitivity interval... and an optical spacing cavity 20 of an Mth sensitivity level in an Mth sensitivity interval;

[0110] The sensor 200 is used to detect the gas inside the optical cavity 20 in the first sensitivity range and output a parameter value representing the oxygen concentration inside the optical cavity 20;

[0111] The gas inlet injects process gas into the gas containing chamber when the parameter value exceeds the preset parameter value, and stops injecting process gas when the parameter value does not exceed the preset parameter value.

[0112] In the embodiment of the present application, a sensor 200 is provided to obtain the oxygen concentration value inside the optical spacer cavity 20 at the strongest position in the sensitivity range of the objective lens. The purity of the process gas inside the objective lens can be determined based on the oxygen concentration value, and the process gas can be adaptively filled into the objective lens, thereby ensuring the purity of the process gas inside the objective lens, and then ensuring the imaging effect and service life of the objective lens.

[0113] It should be noted that the reason why the concentration value of oxygen in the optical interval cavity 20 is monitored in the embodiment of the present application is that oxygen is the most sensitive gas to exposure inside the objective lens. Based on this, by setting the sensor 200 to obtain the concentration value of oxygen inside the objective lens, it is possible to timely determine whether the purity of the process gas inside the objective lens has changed, so that the air intake flow rate of the objective lens can be adjusted and compensated in time. On the one hand, the purity of the process gas in the sensitive part of the optical interval cavity 20 can be effectively monitored. On the other hand, the flow rate of the objective lens filling gas can be timely adjusted and compensated, which can also improve the stability and effectiveness of the internal and external environment monitoring of the objective lens and reduce the gas source consumption cost.

[0114] Specifically, in some embodiments, the sensor 200 includes a dissolved oxygen sensor, which is disposed at a position of the optical compartment cavity 20 in the first sensitivity range, and is used to monitor the oxygen concentration value inside the optical compartment cavity 20 at the most sensitive position.

[0115] In the embodiment of the present application, by arranging a dissolved oxygen sensor at the position of the optical cavity 20 within the first sensitivity range, the oxygen concentration value inside the optical cavity 20 can be monitored in time, so that the process gas concentration inside the optical cavity 20 at the most sensitive position can be monitored in time, so that an appropriate amount of process gas can be filled into the objective lens in time and accurately according to the change of the process gas concentration inside the optical cavity 20, so that the process gas concentration inside the objective lens meets the preset concentration standard.

[0116] Further, in some embodiments, Figure 2 As shown, the objective lens has a plurality of lenses 10 arranged in sequence in the axial direction thereof, and an optical spacing cavity 20 is defined between every two adjacent lenses 10;

[0117] The objective lens further comprises an exhaust port connected to the gas containing chamber, and the exhaust port is controlled to be opened when the gas inlet is fed with gas;

[0118] One of the air inlet and the air outlet is arranged at one end in the axial direction of the objective lens, and the other is arranged at the other end in the axial direction of the objective lens.

[0119] In the embodiment of the present application, the air inlet and the air outlet are arranged at both ends of the objective lens in the axial direction, which has the effect of quickly updating and filling the process gas inside the objective lens.

[0120] Further, in some embodiments, the length of the objective lens in the axial direction is designed to be between 1000 mm and 1500 mm, and the length of the objective lens in the radial direction is designed to be between 500 mm and 800 mm;

[0121] The objective lens with an axial length of 1000 mm to 1500 mm and a radial length of 500 mm to 800 mm defines 20 to 30 optical spacing cavities 20 as described above.

[0122] That is, the above-mentioned object lens has more optical interval cavities 20 inside. In order to effectively monitor the influence of gas purity of the optical interval cavity 20 inside the object lens on the refractive index, the sensitivity detection method of the optical interval {the gap between the lenses} of the lens to the optical index is used in the embodiment of the present application. This method can obtain the sensitivity distribution of each optical interval through optical simulation to determine the position where the purity change inside the object lens causes the most sensitive refractive index; considering that the most sensitive gas for photolithography exposure is oxygen, the oxygen content sensor is arranged to monitor the oxygen concentration of the gap sensitive part to reflect the process gas concentration ice flower inside the object lens, so as to be able to timely adjust and compensate the intake flow of the object lens. On the one hand, the process gas purity of the optical interval sensitive part can be effectively monitored, and on the other hand, the flow of the object lens filling gas {i.e., process gas} can be timely adjusted and compensated, which improves the stability and effectiveness of the internal and external environment monitoring of the object lens and reduces the gas source consumption cost. Compared with the existing gas path purity control scheme, this structure can effectively monitor and control the stability of the gas purity of the object lens and can reduce the gas source consumption cost.

[0123] It should be noted that the objective lens with an axial length of 1000mm-1500mm and a radial length of 500mm-800mm is mainly used in photolithography machines.

[0124] It should also be noted that in the prior art, when detecting the concentration of gas inside the objective lens, an online gas analyzer is usually installed to obtain the gas concentration inside the objective lens. However, the working principle of the online gas analyzer is only based on the selective absorption of infrared rays by certain gases. This detection method cannot be applied to the objective lens of a lithography machine.

[0125] Furthermore, the third aspect of the embodiment of the present application also provides a lithography machine, which includes the objective lens provided in the second aspect of the embodiment of the present application.

[0126] Further, such as Figure 4 As shown, the lithography machine also includes:

[0127] An air control device 300, an air inlet pipe 400 is connected between the air control device 300 and the air inlet of the objective lens;

[0128] The gas control device 300 is used to control whether the gas inlet is inlet according to the parameter value representing the oxygen concentration inside the optical spacer cavity 20 output by the sensor 200.

[0129] Further, such as Figure 4 As shown, in some embodiments, the lithography machine further includes:

[0130] A flow control module 500 connected to the air intake pipe 400, and

[0131] A controller 600 connected between the flow control module 500 and the sensor 200, and

[0132] An exhaust pipe 700 connected between the exhaust port of the objective lens and the gas control device 300;

[0133] The controller 600 is used to adjust the flow control module 500 according to the parameter value representing the oxygen concentration output by the sensor 200, so as to adjust the intake parameters of the air inlet;

[0134] The air intake parameters of the air intake port include the air intake volume and / or the air intake pressure and / or the air intake duration of the air intake port, and the exhaust port is controlled to be opened when the air intake port is taking in air.

[0135] Specific, combined Figure 2-Figure 4 As shown, when the lithography machine is in use, a dissolved oxygen sensor is set at the most sensitive optical spacer cavity 20 to obtain the oxygen concentration value inside the objective lens {that is, a dissolved oxygen sensor is set at the middle position in the axial direction of the objective lens} to reflect the process gas purity stability value and stabilization time at this position inside the objective lens. By monitoring the process gas purity at the sensitive position, the gas control device 300 and the flow control module 500 automatically adjust and compensate the intake flow rate, which can effectively prevent the drift of optical indicators inside the objective lens due to unstable process gas purity, thereby improving the stability and effectiveness of environmental monitoring inside and outside the objective lens, reducing the gas source consumption cost while improving the stability of the optical indicators of the objective lens, and then improving the use accuracy and stability of the lithography machine.

[0136] In the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The steps shown in the relevant flow chart can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flow chart, in some cases, the steps shown or described can be executed in an order different from that here. In other words, the order of steps described in the foregoing embodiments is only an example, and it is also within the scope of protection of the embodiments of the present application to reasonably adjust the order of steps based on the content of the embodiments of the present application.

[0137] The sequence of serial numbers or introduction of the embodiments of the present application is for description only and does not represent the superiority or inferiority of the embodiments.

[0138] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0139] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for detecting gas leakage of an objective lens, characterized in that: A plurality of optical cavities are defined inside the objective lens, and the plurality of optical cavities are interconnected to form a gas containing cavity for containing gas, and the gas containing cavity has a gas inlet, and the gas inlet is used to inject process gas into the gas containing cavity, wherein the plurality of optical cavities include an optical cavities of a first sensitivity level in a first sensitivity interval, an optical cavities of a second sensitivity level in a second sensitivity interval, and an optical cavities of an Mth sensitivity level in an Mth sensitivity interval based on a distribution rule of sensitivity from strong to weak; The gas leakage detection method comprises: Acquire an internal oxygen concentration value of the optical spacer cavity within a first sensitivity interval, and control whether the air inlet is to be inhaled and an air intake parameter of the air inlet when the air inlet is inhaled based on the acquired oxygen concentration value; The air intake parameters of the air intake port include the air intake volume and / or air intake pressure and / or air intake duration of the air intake port; wherein, The first sensitivity interval represents the position interval where the refractive index is most sensitive due to the change in gas purity inside the objective lens; The positions of the multiple optical cavity spaces within the first sensitivity interval can all be identified as the positions most sensitive to the refractive index caused by the purity change of the process gas inside the objective lens.

2. The gas leakage detection method according to claim 1, characterized in that: The first sensitivity interval contains at least one optical compartment cavity at a first sensitivity level; Wherein, when the first sensitivity interval includes a plurality of optical spacing cavities at the first sensitivity level; The step of obtaining the internal oxygen concentration value of the optical spacer cavity within the first sensitivity interval includes: The sensitivity intensities of the plurality of optical compartments in the first sensitivity interval are compared, the optical compartment with the strongest sensitivity is determined based on the comparison result, and the oxygen concentration value in the optical compartment with the strongest sensitivity is obtained.

3. The gas leakage detection method according to claim 1, characterized in that: The step of acquiring an internal oxygen concentration value of the optical spacer cavity within a first sensitivity interval, and controlling whether the air inlet is to be inhaled and an air inlet parameter of the air inlet when inhaling air based on the acquired oxygen concentration value, comprises: Based on the obtained oxygen concentration value, the process gas concentration value in the corresponding optical spacer cavity is calculated, and the opening and closing of the air inlet and the air intake parameters of the air inlet during air intake are controlled according to the process gas concentration value.

4. The gas leakage detection method according to claim 1, characterized in that: The step of acquiring an internal oxygen concentration value of the optical spacer cavity within a first sensitivity interval, and controlling whether the air inlet is to be inhaled and an air inlet parameter of the air inlet when inhaling air based on the acquired oxygen concentration value, comprises: Determining whether the oxygen concentration value is greater than a first preset oxygen concentration value; If the oxygen concentration value is greater than a first preset oxygen concentration value, controlling the air inlet to open; If the oxygen concentration value is less than or equal to the first preset oxygen concentration value, the air inlet is controlled to be closed.

5. The gas leakage detection method according to claim 4, characterized in that: If the oxygen concentration value is greater than a first preset oxygen concentration value, controlling the air inlet to open includes: If the oxygen concentration value is greater than the first preset oxygen concentration value and less than the second preset oxygen concentration value, controlling the air intake to take in air at a first air intake volume per unit time; If the oxygen concentration value is greater than or equal to a second preset oxygen concentration value, controlling the air intake to take in air at a second air intake volume per unit time; The first intake air volume is smaller than the second intake air volume.

6. An objective lens, characterized in that: A gas leakage detection method as described in any one of claims 1 to 5 is adopted.

7. An objective lens, characterized in that: include: An objective lens body, wherein a plurality of optical cavities are defined inside the objective lens body, the plurality of optical cavities are interconnected to form a gas containing cavity for containing gas, the gas containing cavity has a gas inlet, wherein the plurality of optical cavities include, based on a distribution rule of sensitivity from strong to weak, an optical cavities of a first sensitivity level in a first sensitivity interval, an optical cavities of a second sensitivity level in a second sensitivity interval, and an optical cavities of an Mth sensitivity level in an Mth sensitivity interval; A sensor, the sensor is used to detect the gas inside the optical spacer cavity in a first sensitivity range and output a parameter value representing the oxygen concentration inside the optical spacer cavity; The gas inlet injects process gas into the gas containing chamber when the parameter value exceeds the preset parameter value, and stops injecting process gas when the parameter value does not exceed the preset parameter value; wherein, The first sensitivity interval represents the position interval where the refractive index is most sensitive due to the change in gas purity inside the objective lens; The positions of the multiple optical cavity spaces within the first sensitivity interval can all be identified as the positions most sensitive to the refractive index caused by the purity change of the process gas inside the objective lens.

8. The objective lens according to claim 7, characterized in that The sensor comprises a dissolved oxygen sensor, which is arranged at a position of the optical compartment cavity within a first sensitivity interval and is used to monitor the oxygen concentration value inside the optical compartment cavity.

9. The objective lens according to claim 7, characterized in that The objective lens has a plurality of lenses arranged in sequence in the axial direction thereof, and an optical spacing cavity is defined between each two adjacent lenses; The objective lens further comprises an exhaust port connected to the gas containing chamber, and the exhaust port is controlled to be opened when the gas inlet is fed with gas; One of the air inlet and the air outlet is provided at one end in the axial direction of the objective lens, and the other is provided at the other end in the axial direction of the objective lens.

10. The objective lens according to claim 7, characterized in that The length of the objective lens in its axial direction is designed to be between 1000 mm and 1500 mm, and the length of the objective lens in its radial direction is designed to be between 500 mm and 800 mm; The objective lens with an axial length of 1000mm-1500mm and a radial length of 500mm-800mm defines 20-30 optical spacing cavities inside.

11. A photolithography machine, characterized in that: The objective lens comprises the objective lens according to claim 6 or the objective lens according to any one of claims 7 to 10.

12. The photolithography machine according to claim 11, characterized in that: The lithography machine also includes: An air control device, wherein an air inlet pipe is connected between the air control device and the air inlet of the objective lens; The gas control device is used to control whether the air inlet is inlet according to the parameter value output by the sensor that represents the oxygen concentration inside the optical spacer cavity.

13. The lithography machine according to claim 12, characterized in that: The lithography machine also includes: a flow control module connected to the air inlet pipe, and a controller connected between the flow control module and the sensor, and An exhaust pipe connected between the exhaust port of the objective lens and the air control device; The controller is used to adjust the flow control module according to the parameter value representing the oxygen concentration output by the sensor, so as to adjust the intake parameter of the air inlet; The air intake parameters of the air intake port include the air intake volume and / or the air intake pressure and / or the air intake duration of the air intake port, and the exhaust port is controlled to be opened when the air intake port is taking in air.

Images