An apparatus for a vacuum tube in a scanning electron microscope and a scanning electron microscope.

Abstract

This application provides an apparatus for a vacuum tubing in a scanning electron microscope (SEM) and an SEM itself. The apparatus includes a valve seat connected to a first connector, a second connector, a third connector, and a fourth connector. The first connector connects to the outlet of a molecular pump, the second connector connects to the primary inlet of the molecular pump, the third connector connects to a sample chamber, and the fourth connector connects to a mechanical pump. An internal gas channel connects the first connector, the second connector, the third connector, and the fourth connector. The valve seat is also connected to a valve assembly in a first state. In this first state, the first connector and the fourth connector are connected through the gas channel; the first connector, the second connector, and the fourth connector are all disconnected from the third connector.

Description

Technical Field

[0001] This application relates to the field of scanning electron microscopy, and more specifically, to an apparatus for a vacuum tube in a scanning electron microscope and a scanning electron microscope. Background Technology

[0002] Currently, scanning electron microscopes (SEMs) on the market include a sample chamber, a microscope tube, and a vacuum pump. The vacuum pump is used to maintain a vacuum environment within the sample chamber and microscope tube during sample observation. Vacuum pumps include molecular pumps and mechanical pumps. Mechanical pumps are used to evacuate chambers with higher pressure, while molecular pumps are used to evacuate chambers with lower pressure. Both molecular and mechanical pumps include a primary inlet and a secondary inlet. The primary inlet is used to evacuate the sample chamber, and the secondary inlet is used to evacuate the microscope tube.

[0003] When changing samples, the sample chamber opens, bringing the pressure inside to atmospheric pressure, which is higher than the operating pressure of the molecular pump. Therefore, existing scanning electron microscopes require the vacuum pump to be stopped during sample changes. This causes a vacuum leak in the sample chamber and microscope tube, allowing air to gradually enter both.

[0004] The microscope tube contains a tungsten filament lamp. The filament heats up during operation, and contact with air while heated reduces its lifespan. Therefore, existing scanning electron microscopes require the filament to cool down before the vacuum pump can be stopped when changing samples. This means that the tungsten filament lamp must be turned off first, and the vacuum released only after the filament has cooled down, resulting in a sample change time typically exceeding 5 minutes, significantly reducing the user experience. Utility Model Content

[0005] The purpose of this application is to provide a device for a vacuum circuit of a scanning electron microscope and a scanning electron microscope, which can enable sample changing without stopping the molecular pump and vacuum pump, so that the filament is always in a vacuum state, thereby shortening the sample changing time.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, embodiments of this application provide a device for a vacuum pipeline of a scanning electron microscope, including a valve seat, the valve seat being connected to a first connector, a second connector, a third connector and a fourth connector, the first connector being used to connect to the outlet of a molecular pump, the second connector being used to connect to the primary inlet of the molecular pump, the third connector being used to connect to a sample chamber, and the fourth connector being used to connect to a mechanical pump.

[0008] The valve seat has an air passage inside, which connects the first connector, the second connector, the third connector, and the fourth connector.

[0009] The valve seat is also connected to a valve assembly, which has a first state. In the first state, the first connector and the fourth connector are connected through the air passage; the first connector, the second connector, and the fourth connector are all disconnected from the third connector.

[0010] The device provided by the above technical solution is applied to the vacuum tubing of a scanning electron microscope. When the valve assembly is in the first state, the first, second, and fourth connectors are all disconnected from the third connector. Therefore, no gas is drawn from the third connector to the first, second, or fourth connector. In other words, the molecular pump connected to the first and second connectors is not connected to the sample chamber connected to the third connector; similarly, the mechanical pump connected to the fourth connector is not connected to the sample chamber connected to the third connector. Thus, the device provided by the above technical solution can be in the first state during sample changing to isolate the gas path between the molecular pump, mechanical pump, and sample chamber. This allows the molecular pump and mechanical pump to operate normally during sample changing without stopping, maintaining a vacuum environment inside the microscope tube. This ensures the filament remains in a vacuum environment, eliminating the need to wait for the filament to cool down before changing samples, significantly shortening the sample changing time. Furthermore, the constant vacuum environment inside the microscope tube reduces the impact on the tungsten filament lamp's lifespan.

[0011] In some alternative implementations, the valve assembly further has a second state in which the third connector and the fourth connector are in communication via the air passage; and the first connector and the second connector are disconnected from the third connector and the fourth connector.

[0012] When the valve assembly is in the second state, the third connector and the fourth connector are connected through the air passage, enabling the mechanical pump connected to the fourth connector to perform a vacuum operation on the sample chamber connected to the third connector.

[0013] In some alternative implementations, the valve assembly also has a third state in which the second connector and the third connector are connected through the air passage, the first connector and the fourth connector are connected through the air passage, and the third connector and the fourth connector are disconnected.

[0014] When the valve assembly is in the third state, the second and third connectors are connected through a gas passage, and the first and fourth connectors are connected through a gas passage, allowing the sample chamber to be evacuated using a molecular pump and a mechanical pump.

[0015] In some alternative implementations, the first connector and the second connector are located on the same side of the valve seat.

[0016] In the above technical solution, since both the first connector and the second connector are used to connect to the molecular pump, placing the first connector and the second connector on the same side of the valve seat makes it easier to connect the above device to the vacuum line of the scanning electron microscope.

[0017] In some alternative implementations, the third connector is disposed on one side of the valve seat, and the fourth connector is disposed on the opposite side of the valve seat. The air passage includes a first air passage that runs through the valve seat in a straight line. One end of the first air passage is connected to the third connector, and the other end is connected to the fourth connector.

[0018] In the above technical solution, the third connector and the fourth connector are connected by the first air passage that runs straight through the valve seat, which facilitates the processing of the valve seat.

[0019] In some optional implementations, the airway further includes a second airway and a third airway arranged in parallel, one end of the second airway being connected to the first connector and the other end being connected to the first airway, the connection position being denoted as the first position; one end of the third airway being connected to the second connector and the other end being connected to the first airway, the connection position being denoted as the second position.

[0020] In the above technical solution, since the second and third air passages are arranged in parallel, it is convenient to process the second and third air passages on the valve seat.

[0021] In some alternative embodiments, the valve assembly includes a first valve, a second valve, and a third valve; the first valve is disposed between a first position and a second position in the first air passage; the second valve is disposed in the second air passage; and the third valve is disposed in the third air passage.

[0022] By setting the valve assembly at the location provided by the above technical solution, the valve assembly can have a first state, a second state, and a third state.

[0023] In some optional embodiments, the valve seat is further provided with a through hole located between the second air passage and the third air passage; and the extension direction of the through hole is perpendicular to the extension direction of the first air passage and the second air passage.

[0024] In the above technical solution, the through hole provided on the valve seat can reduce weight and thus reduce the weight of the device.

[0025] In a second aspect, embodiments of this application provide a scanning electron microscope, including a molecular pump, a mechanical pump, and a sample chamber, as well as a device for a vacuum pipeline of a scanning electron microscope provided in the first aspect, wherein the first connector is connected to the outlet of the molecular pump, the second connector is connected to the primary inlet of the molecular pump, the third connector is used to connect to the sample chamber, and the fourth connector is connected to the mechanical pump.

[0026] When the valve assembly is in the first state, the gas path connecting the sample chamber to the mechanical pump and the gas path connecting the molecular pump are both disconnected;

[0027] When the valve assembly is in the second state, the mechanical pump can expel air from the sample chamber.

[0028] When the valve assembly is in the third state, the sample chamber is connected to the molecular pump through the gas passage, and the molecular pump is connected to the mechanical pump through the gas passage.

[0029] The scanning electron microscope provided by the above technical solution allows for sample replacement within the sample chamber without shutting down the molecular and mechanical pumps, ensuring the microscope tube and filament remain under vacuum, thus reducing filament lifespan loss. Furthermore, sample observation can commence shortly after sample replacement, shortening the time required from sample replacement to sample observation. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram showing the connection of a portion of the scanning electron microscope structure provided in an embodiment of this application;

[0032] Figure 2 A schematic diagram of the apparatus provided in an embodiment of this application from a first-view perspective;

[0033] Figure 3 A schematic diagram of the apparatus provided in an embodiment of this application from a second perspective;

[0034] Figure 4 A schematic diagram of the apparatus provided in an embodiment of this application from a third-person perspective;

[0035] Figure 5 This is a schematic diagram of the valve seat provided in an embodiment of this application.

[0036] Icons: 100 - Apparatus; 110 - Valve seat; 111 - First gas passage; 112 - Second gas passage; 113 - Third gas passage; 114 - Through hole; 121 - First connector; 122 - Second connector; 123 - Third connector; 124 - Fourth connector; 131 - First valve; 132 - Second valve; 133 - Third valve; 200 - Molecular pump; 300 - Mechanical pump; 400 - Lens tube; 500 - Sample chamber. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this application, it should be noted that the terms "center," "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0042] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] Currently, during sample changes in scanning electron microscopes (SEMs), the sample chamber is open to the atmosphere. However, the molecular pump operates at a relatively low pressure, making it impossible to perform vacuuming at atmospheric pressure. Therefore, both the molecular and mechanical pumps must be shut down during sample changes. After the sample is changed, the mechanical pump is used to evacuate the sample chamber until the pressure drops to a level suitable for the molecular pump. Then, the molecular pump is used to evacuate the sample chamber again before finally activating the electron gun. After the molecular pump stops, the microscope tube gradually de-vacuums, allowing air to enter. This exposes the tungsten lamp filament to air, which, if exposed at a high temperature, reduces its lifespan. Therefore, using existing SEMs requires shutting down the tungsten lamp and waiting for it to cool before shutting down the molecular and mechanical pumps, resulting in excessively long sample changes and potentially impacting the tungsten lamp's lifespan.

[0044] Based on this, this application provides a scanning electron microscope, including a device for the vacuum pipeline of the scanning electron microscope, which enables the molecular pump and mechanical pump to continue running during sample changing. Therefore, the filament can be kept in a vacuum environment without waiting for the filament to cool down before the sample chamber can be opened for sample changing, thus shortening the sample changing time and reducing the loss of filament life.

[0045] The scanning electron microscope provided in this application is as follows: Figure 1 As shown, it includes a molecular pump 200, a mechanical pump 300, a sample chamber 500, and a device 100 installed in the vacuum tubing of the scanning electron microscope.

[0046] like Figures 2 to 4As shown, the device 100 includes a valve seat 110, which is connected to a first connector 121, a second connector 122, a third connector 123, and a fourth connector 124. The first connector 121 is connected to the outlet of the molecular pump 200, the second connector 122 is connected to the primary inlet of the molecular pump 200, the third connector 123 is connected to the sample chamber 500, and the fourth connector 124 is connected to the mechanical pump 300. The first connector 121, the second connector 122, the third connector 123, and the fourth connector 124 can be directly connected to the outlet of the corresponding molecular pump 200, the primary inlet of the molecular pump 200, the sample chamber 500, and the mechanical pump 300, or they can be connected via pipes.

[0047] like Figure 5 As shown, the valve seat 110 also has an air passage (i.e., Figure 5 (The structure shown by the dashed line) The air passage connects the first connector 121, the second connector 122, the third connector 123, and the fourth connector 124. That is, any two of the first connector 121, the second connector 122, the third connector 123, and the fourth connector 124 can be connected through the air passage, so that gas can move from any of the four connectors to the other one.

[0048] The device 100 also includes a valve assembly connected to the valve seat 110 and having a first state. In the first state, the first connector 121 and the fourth connector 124 are connected through a gas passage; the first connector 121, the second connector 122, and the fourth connector 124 are all disconnected from the third connector 123, that is, gas cannot move from the third connector 123 to any of the first connector 121, the second connector 122, and the fourth connector 124 through the gas passage in the valve seat 110. When the valve assembly is in the first state, the molecular pump 200 is not connected to the sample chamber 500. Therefore, even when the sample chamber 500 is opened for sample replacement, the molecular pump 200 can continue operating without interruption. The molecular pump 200 and the mechanical pump 300 are connected through the first connector 121 and the fourth connector 124 for normal operation, maintaining a vacuum environment inside the microscope tube 400 where the filament is located. Therefore, the scanning electron microscope provided in this application can achieve the goal of not turning off the molecular pump 200 and the mechanical pump 300 during sample change, and the inside of the microscope tube 400 where the filament is located remains a vacuum environment, which can reduce the time spent in the sample change process and reduce the life loss of the filament.

[0049] like Figure 1 As shown, the scanning electron microscope provided in this application also includes a microscope tube 400, in which a filament is provided. The secondary air inlet of the molecular pump 200 and the secondary air inlet of the mechanical pump 300 are both connected to the microscope tube 400 to evacuate the inside of the microscope tube 400. Figure 1The curve connecting the molecular pump 200 and the mirror barrel 400 is a simplified schematic diagram of the pipe connecting the secondary air inlet of the molecular pump 200 and the mirror barrel 400; the curve connecting the molecular pump 200 and the device 100 is a simplified schematic diagram of the pipe connecting the primary air inlet of the molecular pump 200 and the device 100; the curve connecting the mechanical pump 300 and the mirror barrel 400 is a simplified schematic diagram of the pipe connecting the secondary air inlet of the mechanical pump 300 and the mirror barrel 400; the curve connecting the mechanical pump 300 and the device 100 is a simplified schematic diagram of the pipe connecting the primary air inlet of the mechanical pump 300 and the device 100.

[0050] In some embodiments of this application, the valve assembly also has a second state. In the second state, the third connector 123 and the fourth connector 124 are connected through an air passage; the first connector 121 and the second connector 122 are both disconnected from the third connector 123 and the fourth connector 124. That is, the third connector 123 and the fourth connector 124 are connected through an air passage, allowing the mechanical pump 300 connected to the fourth connector 124 to perform a vacuuming operation on the sample chamber 500 connected to the third connector 123. In the second state, the mechanical pump 300 can expel the air from the sample chamber 500, enabling vacuuming of the sample chamber 500 after sample replacement; in the second state, the first connector 121 and the second connector 122 connected to the molecular pump 200 are both disconnected from the third connector 123 and the fourth connector 124, therefore, the molecular pump 200 will not be connected to a pipeline with a high air pressure.

[0051] In some embodiments of this application, the valve assembly also has a third state. In the third state, the second connector 122 and the third connector 123 are connected through a gas passage, the first connector 121 and the fourth connector 124 are connected through a gas passage, and the third connector 123 and the fourth connector 124 are disconnected. When the valve assembly is in the third state, the primary air inlet of the molecular pump 200 can be connected to the sample chamber 500 through the gas passage in the valve body to further evacuate the sample chamber 500, so that the vacuum level in the sample chamber 500 reaches the requirement for viewing the image.

[0052] Some of the implementation methods provided in this application, such as Figures 2 to 4 As shown, the first connector 121 and the second connector 122 are disposed on one side of the valve seat 110. Since both the first connector 121 and the second connector 122 are used to connect the molecular pump 200, disposing of the first connector 121 and the second connector 122 on the same side of the valve seat 110 facilitates connecting the valve seat 110 to the vacuum tubing of the scanning electron microscope. In other embodiments, the first connector 121 and the second connector 122 may also be disposed on different sides of the valve seat 110.

[0053] In some embodiments provided in this application, the third connector 123 is disposed on one side of the valve seat 110, and the fourth connector 124 is disposed on the opposite side of the valve seat 110. For example... Figure 5 As shown, the air passage within the valve seat 110 includes a first air passage 111, which runs through the valve seat 110 in a straight line. One end of the first air passage 111 is connected to a third connector 123, and the other end is connected to a fourth connector 124. In this embodiment, the first air passage 111 runs through the valve seat 110 in a straight line, which facilitates the machining of the first air passage 111. In other embodiments, the first air passage 111 may not run through the valve seat 110 in a straight line.

[0054] In some embodiments, the air passage further includes a second air passage 112 and a third air passage 113 arranged in parallel. One end of the second air passage 112 is connected to the first connector 121, and the other end is connected to the first air passage 111, denoted as the first position. One end of the third air passage 113 is connected to the second connector 122, and the other end is connected to the first air passage 111, denoted as the second position. Since the second air passage 112 and the third air passage 113 are arranged in parallel, it is convenient to machine the second air passage 112 and the third air passage 113 on the valve seat 110.

[0055] Furthermore, the valve assembly includes a first valve 131, a second valve 132, and a third valve 133; the first valve 131 is disposed between a first position and a second position of the first air passage 111; the second valve 132 is disposed in the second air passage 112; and the third valve 133 is disposed in the third air passage 113. In some embodiments, the first valve 131, the second valve 132, and the third valve 133 are all electrically operated gate valves; in other embodiments, the first valve 131, the second valve 132, and the third valve 133 may also be other types of valves.

[0056] like Figures 2 to 4 As shown, with the first valve 131 and the third valve 133 closed and the second valve 132 open, the air passage between the first connector 121 and the fourth connector 124 is connected, and the first connector 121, the second connector 122, and the fourth connector 124 are all disconnected from the third connector 123. At this time, the valve assembly is in the first state. With the first valve 131 open and the second valve 132 and the third valve 133 closed, the third connector 123 and the fourth connector 124 are connected, and the first connector 121 and the second connector 122 are all disconnected from the third connector 123 and the fourth connector 124. At this time, the valve assembly is in the second state. With the first valve 131 closed and the second valve 132 and the third valve 133 open, the first connector 121 and the fourth connector 124 are connected through an air passage, the second connector 122 and the third connector 123 are connected through an air passage, and the third connector 123 and the fourth connector 124 are disconnected.

[0057] Furthermore, the valve seat 110 is also provided with a through hole 114, which is located between the second air passage 112 and the third air passage 113, and the extending direction of the through hole 114 is perpendicular to the extending direction of the first air passage 111 and the second air passage 112. This through hole 114 can act as a weight-reducing hole to reduce the weight of the valve seat 110.

[0058] The sample changing operation using the scanning electron microscope provided in the embodiments of this application includes:

[0059] S1: Close the first valve 131 and the third valve 133, and open the second valve 132 to put the valve assembly in the first state. At this time, the molecular pump 200 is not connected to the sample chamber 500, and the sample chamber 500 can be opened for sample replacement.

[0060] S2: After placing the new sample to be observed into the sample chamber 500, close the sample chamber 500, open the first valve 131, and close the second valve 132 and the third valve 133. At this time, the valve assembly is in the second state. The sample chamber 500 connected to the third connector 123 is connected to the mechanical pump 300 connected to the fourth connector 124, so that the mechanical pump 300 evacuates the sample chamber 500.

[0061] S3: Close the first valve 131 and open the second valve 132 and the third valve 133. At this time, the valve assembly is in the third state, and the second connector 122 and the third connector 123 are connected, so that the molecular pump 200 can further evacuate the sample chamber 500. When the vacuum of the sample chamber 500 reaches the requirements for viewing the image, open the gun valve and tungsten filament lamp of the microscope tube 400, and then start observing the sample.

[0062] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An apparatus for a vacuum tube in a scanning electron microscope, characterized in that, Includes a valve seat, which is connected to a first connector, a second connector, a third connector and a fourth connector. The first connector is used to connect to the outlet of the molecular pump, the second connector is used to connect to the first-stage inlet of the molecular pump, the third connector is used to connect to the sample chamber, and the fourth connector is used to connect to the mechanical pump. The valve seat has an air passage inside, which connects the first connector, the second connector, the third connector, and the fourth connector. The valve seat is also connected to a valve assembly, which has a first state in which the first connector and the fourth connector are connected through the air passage; the first connector, the second connector, and the fourth connector are all disconnected from the third connector.

2. The apparatus according to claim 1, characterized in that, The valve assembly also has a second state; in the second state, the third connector and the fourth connector are connected through the air passage; the first connector and the second connector are both disconnected from the third connector and the fourth connector.

3. The apparatus according to claim 2, characterized in that, The valve assembly also has a third state in which the second connector and the third connector are connected through the air passage, the first connector and the fourth connector are connected through the air passage, and the third connector and the fourth connector are disconnected.

4. The apparatus according to claim 3, characterized in that, The first connector and the second connector are located on the same side of the valve seat.

5. The apparatus according to claim 3, characterized in that, The third connector is located on one side of the valve seat, and the fourth connector is located on the opposite side of the valve seat.

6. The apparatus according to claim 5, characterized in that, The air passage includes a first air passage that runs straight through the valve seat; one end of the first air passage is connected to the third connector and the other end is connected to the fourth connector.

7. The apparatus according to claim 6, characterized in that, The airway also includes a second airway and a third airway arranged in parallel. One end of the second airway is connected to the first connector, and the other end is connected to the first airway. The connection position is denoted as the first position. One end of the third airway is connected to the second connector, and the other end is connected to the first airway. The connection position is denoted as the second position.

8. The apparatus according to claim 7, characterized in that, The valve assembly includes a first valve, a second valve, and a third valve; the first valve is disposed between a first position and a second position in the first air passage; the second valve is disposed in the second air passage; and the third valve is disposed in the third air passage.

9. The apparatus according to claim 7, characterized in that, The valve seat is also provided with a through hole, which is located between the second air passage and the third air passage; and the extension direction of the through hole is perpendicular to the extension direction of the first air passage and the second air passage.

10. A scanning electron microscope, characterized in that, The device includes a molecular pump, a mechanical pump, and a sample chamber, as well as the apparatus for a vacuum pipeline for a scanning electron microscope provided by any one of claims 3-9, wherein the first connector is connected to the outlet of the molecular pump, the second connector is connected to the primary inlet of the molecular pump, the third connector is used to connect to the sample chamber, and the fourth connector is connected to the mechanical pump. When the valve assembly is in the first state, the gas path connecting the sample chamber to the mechanical pump and the gas path connecting the molecular pump are both disconnected; When the valve assembly is in the second state, the mechanical pump can expel air from the sample chamber. When the valve assembly is in the third state, the sample chamber is connected to the molecular pump through the gas passage, and the molecular pump is connected to the mechanical pump through the gas passage.

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