Scanning electron microscope objective

Abstract

The present invention discloses a scanning electron microscope objective lens, the scanning electron microscope objective lens comprises: an upper pole shoe assembly of the objective lens, the upper pole shoe assembly of the objective lens has a hollow cavity and a first connection port, a vacuum tube is arranged in the hollow cavity, the vacuum tube is used to communicate with an electron beam generating chamber, the end of the vacuum tube extends to the first connection port, the first connection port is provided with a first diaphragm; a lower pole shoe of the objective lens, the lower pole shoe of the objective lens is provided with a second connection port, the second connection port is used to communicate with the internal space of a sample chamber, the second connection port is provided with a second diaphragm; an interlayer cavity is formed between the upper pole shoe assembly of the objective lens and the lower pole shoe of the objective lens, the first diaphragm and the second diaphragm are both provided with diaphragm holes communicating with the interlayer cavity, and the interlayer cavity has a vacuum port. The scanning electron microscope objective lens of the present invention forms an evacuable interlayer cavity between the upper pole shoe assembly of the objective lens and the lower pole shoe of the objective lens, which is beneficial to increase the air pressure difference between the vacuum tube and the inner space of the sample chamber.

Description

Technical Field

[0001] The invention relates to the technical field of optical detection instruments, in particular to a scanning electron microscope objective lens. Background Art

[0002] The principle of scanning electron microscopy is to obtain information on various physical and chemical properties of the sample itself based on the interaction between electrons and matter. When observing some non-conductive and water-containing samples, the scanning electron microscope requires the sample chamber to be in a low vacuum environment, and it should be noted that the sample chamber is in a connected state with the electron tube and the electron gun. Therefore, it is necessary to achieve variable vacuum in the sample chamber and maintain a high vacuum state in the electron gun and the tube. In the current design, the air pressure value in the sample chamber cannot meet the requirements of some water-containing samples for a vacuum environment during sampling, and it cannot guarantee that the sample will not be dehydrated when observed in the sample chamber, so there is room for improvement. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a scanning electron microscope objective lens that can increase the vacuum difference between the sample chamber and the vacuum tube, thereby facilitating accurate detection of some water-containing samples.

[0004] A scanning electron microscope objective lens according to an embodiment of the present invention comprises: an upper pole shoe assembly of the objective lens, the upper pole shoe assembly of the objective lens having a hollow cavity and a first connecting port, a vacuum tube being arranged in the hollow cavity, the vacuum tube being used to communicate with an electron beam generating chamber, and the end of the vacuum tube extending to the first connecting port, the first connecting port being provided with a first aperture; a lower pole shoe of the objective lens, the lower pole shoe of the objective lens being provided with a second connecting port, the second connecting port being used to communicate with an internal space of a sample chamber, the second connecting port being provided with a second aperture; an interlayer cavity is formed between the upper pole shoe assembly of the objective lens and the lower pole shoe of the objective lens, the first aperture and the second aperture are both provided with aperture holes communicating with the interlayer cavity, and the interlayer cavity has a vacuum port.

[0005] According to the scanning electron microscope objective lens of the embodiment of the present invention, an interlayer cavity is formed between the upper pole shoe of the objective lens and the lower pole shoe of the objective lens. By evacuating the interlayer cavity, the air pressure difference between the internal space of the vacuum tube and the sample chamber can be increased, so that the vacuum environment in the vacuum tube can meet the sampling requirements of some water-containing samples. At the same time, it can effectively reduce the fluctuation effect of the vacuum environment in the vacuum tube when the air pressure in the sample chamber changes.

[0006] According to some embodiments of the scanning electron microscope objective of the present invention, the upper pole shoe assembly of the objective lens includes an upper pole shoe of the objective lens and a vacuum connecting cavity, the upper pole shoe of the objective lens is connected to the lower pole shoe of the objective lens, the vacuum connecting cavity is connected to one end of the upper pole shoe of the objective lens away from the lower pole shoe of the objective lens, the vacuum port is arranged in the vacuum connecting cavity, and the first connecting port is arranged on the upper pole shoe of the objective lens.

[0007] According to some embodiments of the scanning electron microscope objective of the present invention, the upper pole shoe of the objective lens includes an inner layer part and an outer layer part, the outer layer part is sleeved on the outside of one end of the inner layer part, and the lower pole shoe of the objective lens is sleeved on the outside of the other end of the inner layer part and is connected to the outer layer part; wherein the interlayer cavity includes a first sub-cavity, an intermediate sub-cavity and a second sub-cavity, the first sub-cavity is formed in the vacuum connecting cavity, the intermediate sub-cavity is formed between the inner layer part and the outer layer part, and the second sub-cavity is formed between the inner layer part and the lower pole shoe of the objective lens.

[0008] According to the scanning electron microscope objective lens of some embodiments of the present invention, the hollow cavity includes a first hollow cavity located in the inner layer part and a second hollow cavity located in the vacuum connecting cavity, the first connecting port is connected to the first hollow cavity, the second hollow cavity is connected to an end of the first hollow cavity away from the first connecting port, and the end of the second hollow cavity away from the first hollow cavity is connected to the external space of the sample chamber.

[0009] According to the scanning electron microscope objective lens of some embodiments of the present invention, the outer peripheral wall of the outer layer portion is provided with a mounting protrusion, and the mounting protrusion is used to be connected to the peripheral wall of the sample chamber.

[0010] According to some embodiments of the scanning electron microscope objective lens of the present invention, the first connecting port and the second connecting port are arranged opposite to each other in the length direction of the scanning electron microscope objective lens.

[0011] According to some embodiments of the present invention, the scanning electron microscope objective lens also includes: a mounting bracket, the first end of the mounting bracket is located in the first connecting port, and the second end of the mounting bracket is located in the second connecting port; the first aperture is passed through the first end of the mounting bracket, the second aperture is passed through the second end of the mounting bracket, and the middle part of the mounting bracket has a connecting port connected to the interlayer cavity.

[0012] According to some embodiments of the scanning electron microscope objective lens of the present invention, there are multiple communication ports, and the multiple communication ports are distributed and spaced apart in the circumferential direction of the mounting bracket.

[0013] According to some embodiments of the scanning electron microscope objective lens of the present invention, a sealing core is provided in the first connecting port, and the sealing core is sleeved outside the first end of the mounting bracket.

[0014] According to some embodiments of the scanning electron microscope objective lens of the present invention, a support member is provided between an end surface of one end of the sealing bushing and an inner end surface of the lower pole shoe of the objective lens.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 is a schematic structural diagram of a scanning electron microscope objective lens according to an embodiment of the present invention;

[0018] Figure 2 It is an enlarged view of the scanning electron microscope objective lens at the aperture according to an embodiment of the present invention.

[0019] Reference numerals:

[0020] SEM objective lens 100,

[0021] Objective lens upper pole shoe assembly 1, objective lens upper pole shoe 11, inner layer part 111, outer layer part 112, mounting convex part 1121, mounting convex ring 1122, first connection port 113, vacuum connection cavity 12, vacuum port 13, interlayer cavity 14, first sub-cavity 141, middle sub-cavity 142, second sub-cavity 143, hollow cavity 15, first hollow cavity 151, second hollow cavity 152,

[0022] The objective lens lower pole piece 2, the second connecting port 21, the mounting ring groove 22, the first aperture 3, the second aperture 4, the support 5, the mounting bracket 6, the sealing core 7, the excitation coil 8, and the vacuum tube 9. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, and examples of the embodiments 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] Reference below Figure 1-Figure 2 The scanning electron microscope objective lens 100 according to an embodiment of the present invention is described, comprising: an objective lens upper pole shoe assembly 1 and an objective lens lower pole shoe 2.

[0025] The objective lens upper pole shoe assembly 1 has a hollow cavity 15 and a first connection port 113. A vacuum tube 9 is provided in the hollow cavity 15. The vacuum tube 9 is used to communicate with the electron beam generating chamber. The end of the vacuum tube 9 extends to the first connection port 113. Figure 1 As shown, the first connection port 113 is provided at the lower end of the upper pole shoe assembly 1 of the objective lens, the upper end of the vacuum tube 9 can be connected to the electron beam generating chamber, and the lower end of the vacuum tube 9 extends to the first connection port 113. It should be noted that the part of the hollow cavity 15 located outside the vacuum tube 9 is connected to the external space of the sample chamber, the vacuum tube 9 is used to connect to the electron beam generating chamber, and the electron gun can be installed on the outer side of the upper pole shoe assembly 1 of the objective lens, such as the electron gun installed on the Figure 1 At the upper part of the upper pole piece assembly 1 of the middle objective lens, the electron beam generated by the electron gun can enter the first connecting port 113 from the vacuum tube 9 and then enter the sample chamber.

[0026] The first connection port 113 is provided with a first aperture 3, and the first aperture 3 is provided with an aperture hole. The aperture hole can connect the tube cavity of the vacuum tube 9 with the space below the first connection port 113 at the first connection port 113, that is, the electron beam in the electron beam generating chamber can be emitted from the vacuum tube 9 to the first aperture 3 and emitted from the aperture hole of the first aperture 3 toward the lower pole shoe 2 of the objective lens. In addition, the lower pole shoe 2 of the objective lens is provided with a second connection port 21, and the second connection port 21 is used to communicate with the internal space of the sample chamber, and the second connection port 21 is provided with a second aperture 4. Figure 1 As shown, the second connection port 21 is provided at the lower end of the objective lens lower pole shoe 2, and the second connection port 21 penetrates the objective lens lower pole shoe 2 in the up-down direction, that is, the second connection port 21 can connect the space above and below it, wherein it should be noted that the space below the second connection port 21 is the internal space of the sample chamber, and the space above the second connection port 21 is the space facing the objective lens upper pole shoe assembly 1. Wherein, by arranging the second aperture 4 at the second connection port 21, the electron beam at the first connection port 113 can be emitted to the sample chamber below the second connection port 21 through the second aperture 4. Wherein, the second aperture 4 can be constructed in a cone shape, which can ensure that the vacuum environment on the path before the electron beam passes through the aperture hole of the second aperture 4 is excellent, and the shape constructed by the second aperture 4 can also cooperate with the low vacuum secondary electron detector and the backscattering detector.

[0027] Furthermore, an interlayer cavity 14 is formed between the upper pole shoe assembly 1 of the objective lens and the lower pole shoe 2 of the objective lens, and the interlayer cavity 14 is respectively connected to the first connection port 113 and the second connection port 21, and the interlayer cavity 14 has a vacuum port 13. It should be noted that the aperture of the first aperture 3 can connect the interlayer cavity 14 with the tube cavity of the vacuum tube 9, and at the same time, the aperture of the second aperture 4 can connect the interlayer cavity 14 with the internal space of the sample chamber, and when observing the sample chamber, the electron beam emitted by the electron gun is emitted from the vacuum tube 9 to the first aperture 3, and is emitted from the aperture hole of the first aperture 3 to the interlayer cavity 14, and then enters the second aperture 4, and finally emitted from the aperture hole of the second aperture 4 to the internal space of the sample chamber, so as to facilitate the test reaction.

[0028] Among them, a corresponding vacuum pump is arranged in the vacuum tube 9 to evacuate the vacuum tube 9, so that a vacuum environment is formed in the vacuum tube 9, which is conducive to the emission of the electron beam. At the same time, a vacuum port 13 is arranged in the interlayer cavity 14, and a vacuum pump can be arranged at the vacuum port 13 to evacuate the interlayer cavity 14 through the vacuum pump, so that the interlayer cavity 14 forms a buffer cavity between the vacuum tube 9 and the internal space of the sample chamber, that is, the tube cavity of the vacuum tube 9, the interlayer cavity 14 and the internal space of the sample chamber form a three-level large gradient vacuum difference. Therefore, by forming the interlayer cavity 14, it is conducive to achieving a larger difference in vacuum between the electron beam generating chamber and the internal space of the sample chamber, thereby reducing the fluctuation effect of the air pressure in the sample chamber on the vacuum in the electron cavity when the air pressure in the sample chamber changes, and ensuring that the sample is not dehydrated during observation in the sample chamber.

[0029] It can be understood that in this embodiment, only a layer of annular vacuum area is set between the upper shoe assembly 1 of the objective lens and the lower shoe 2 of the objective lens, that is, the above-mentioned interlayer cavity 14, and a large vacuum differential can be achieved through the cooperation between the first aperture 3 and the second aperture 4 and the external vacuum pump. In other words, in this embodiment, by reducing the number of vacuum areas between the apertures, the number and type of vacuum pumps required to evacuate the vacuum areas are reduced. That is, a large vacuum differential can be achieved without adding an additional pump group, thereby simplifying the structure of the scanning electron microscope objective 100, reducing the manufacturing cost, and facilitating later maintenance.

[0030] According to the scanning electron microscope objective 100 of the embodiment of the present invention, an interlayer cavity 14 is formed between the upper pole shoe 11 of the objective lens and the lower pole shoe 2 of the objective lens. By evacuating the interlayer cavity 14, the pressure difference between the internal space of the vacuum tube 9 and the sample chamber can be increased, so that the vacuum environment in the vacuum tube 9 can meet the sampling requirements of some water-containing samples, and at the same time, the fluctuation effect of the vacuum environment in the vacuum tube 9 when the air pressure in the sample chamber changes can be effectively reduced.

[0031] In some embodiments, the objective lens upper pole shoe assembly 1 includes an objective lens upper pole shoe 11 and a vacuum connecting cavity 12, the objective lens upper pole shoe 11 is connected to the objective lens lower pole shoe 2, and the vacuum connecting cavity 12 is connected to one end of the objective lens upper pole shoe 11 away from the objective lens lower pole shoe 2.

[0032] It should be noted that if Figure 1 As shown, the upper pole shoe 11 of the objective lens, the lower pole shoe 2 of the objective lens and the vacuum connection cavity 12 are all constructed as a cylindrical structure, wherein the upper pole shoe 11 of the objective lens is located between the lower pole shoe 2 of the objective lens and the vacuum connection cavity 12. In this embodiment, the upper pole shoe 11 of the objective lens and the lower pole shoe 2 of the objective lens are connected in an end-embedded manner, such as Figure 1As shown, a mounting convex ring 1122 is formed at the lower end of the upper pole shoe 11 of the objective lens, and a mounting annular groove 22 is formed at the upper end of the lower pole shoe 2 of the objective lens. When the upper pole shoe 11 of the objective lens is connected with the lower pole shoe 2 of the objective lens, the mounting convex ring 1122 extends into the mounting annular groove 22 to increase the end contact area of ​​the upper pole shoe 11 of the objective lens and the lower pole shoe 2 of the objective lens, thereby improving the connection strength. In addition, the upper pole shoe 11 of the objective lens and the vacuum connection cavity 12 can be connected by bolt fastening, and the sealing of the mating surface is ensured by a sealing ring.

[0033] A vacuum port 13 is provided on the peripheral wall of the vacuum connection cavity 12, and the vacuum port 13 is connected to the interlayer cavity 14. For example, a vacuum pump is connected to the vacuum connection cavity 12 to dock with the vacuum port 13, thereby achieving vacuuming of the interlayer cavity 14. The first connection port 113 is provided on the upper pole shoe 11 of the objective lens, wherein the airflow formed by the aperture of the first aperture 3 located at the first connection port 113 is small, thereby forming a pressure difference between the tube cavity of the vacuum tube 9 and the interlayer cavity 14, and enhancing the vacuum difference of the tube cavity of the vacuum tube 9 relative to the internal space of the sample chamber.

[0034] In some embodiments, the upper pole shoe 11 of the objective lens includes an inner layer portion 111 and an outer layer portion 112, the outer layer portion 112 is sleeved outside one end of the inner layer portion 111, and the lower pole shoe 2 of the objective lens is sleeved outside the other end of the inner layer portion 111 and connected to the outer layer portion 112. Figure 1 As shown, the upper pole shoe 11 of the objective lens is formed into a two-part structure from the outside to the inside. The inner part 111 is a hollow structure in which the vacuum tube 9 is located, and the outer part 112 is constructed in a circular ring shape and is sleeved outside the upper end of the inner part 111.

[0035] The lower end of the outer layer part 112 is connected to the upper end of the lower pole shoe 2 of the objective lens, and a matching structure of a mounting convex ring 1122 and a mounting ring groove 22 is formed at the connection. The upper end of the outer layer part 112 is connected to the outer ring part of the lower end surface of the vacuum connection cavity 12. At the same time, the upper end of the inner layer part 111 is connected to the inner ring part of the lower end surface of the vacuum connection cavity 12, and a first connection port 113 is provided at the lower end of the inner layer part 111. The first connection port 113 is spaced apart from the second connection port 21 provided on the lower pole shoe 2 of the objective lens, and the inner layer part 111 is spaced apart from the lower pole shoe 2 of the objective lens and the outer layer part 112 to form an interlayer cavity 14. In addition, an excitation coil 8 is provided on the outer sleeve of the inner layer part 111 of the upper pole shoe 11 of the objective lens, and the excitation coil 8 is relatively fixed to the inner layer part 111 and spaced apart from the outer layer part 112.

[0036] The sandwich cavity 14 includes a first sub-cavity 141, an intermediate sub-cavity 142, and a second sub-cavity 143. The first sub-cavity 141 is formed in the vacuum connection cavity 12, that is, the first sub-cavity 141 is formed between the inner circle part and the outer circle part of the vacuum connection cavity 12. The intermediate sub-cavity 142 is formed between the inner layer part 111 and the outer layer part 112, and the second sub-cavity 143 is formed between the inner layer part 111 and the lower pole shoe 2 of the objective lens. Figure 1 As shown, the first sub-cavity 141, the middle sub-cavity 142 and the second sub-cavity 143 are sequentially distributed in the up-down direction, the first sub-cavity 141 is open downward to communicate with the upper end of the middle sub-cavity 142, and the lower end of the middle sub-cavity 142 is communicated with the upper end of the second sub-cavity 143 to form a sandwich cavity 14. The excitation coil 8 is sleeved outside the inner layer part 111, and the upper part of the excitation coil 8 is located in the middle sub-cavity 142, and the lower part is located in the second sub-cavity 143.

[0037] The vacuum port 13 of the vacuum connection cavity 12 is connected to the first sub-cavity 141 , so as to evacuate the first sub-cavity 141 , the middle sub-cavity 142 and the second sub-cavity 143 through the vacuum port 13 , which is beneficial for the interlayer cavity 14 to form a buffer cavity.

[0038] In some embodiments, the hollow cavity 15 includes a first hollow cavity 151 and a second hollow cavity 152, the first hollow cavity 151 is disposed in the inner layer portion 111, the second hollow cavity 152 is disposed in the vacuum connecting cavity body 12, the first connecting port 113 is connected to the first hollow cavity 151, the second hollow cavity 152 is connected to an end of the first hollow cavity 151 away from the first connecting port 113, and the end of the second hollow cavity 152 away from the first hollow cavity 151 is connected to the external space of the sample chamber.

[0039] like Figure 1 As shown, the vacuum tube 9 is installed in the hollow cavity 15, and the upper end of the vacuum tube 9 is located in the second hollow cavity 152, and the lower end of the vacuum tube 9 is located in the first hollow cavity 151. Figure 1 As shown, the lower end of the first hollow cavity 151 is connected to the first connection port 113, the upper end of the first hollow cavity 151 is connected to the second hollow cavity 152, and the upper end of the second hollow cavity 152 is connected to the external space of the sample chamber. In this way, the installation of the vacuum tube 9 is achieved, and the electron beam emitted by the electron gun is facilitated to be transmitted in the upper pole shoe assembly 1 of the objective lens.

[0040] In some embodiments, the outer peripheral wall of the outer layer portion 112 is provided with a mounting protrusion 1121, and the mounting protrusion 1121 is used to connect with the peripheral wall of the sample chamber. Figure 2As shown, the mounting protrusion 1121 is radially protruding outward from the outer peripheral wall of the outer layer 112, and the mounting protrusion 1121 is configured as an annular structure. During actual installation, one end surface of the mounting protrusion 1121 can be fitted and fixed to the peripheral wall of the sample chamber.

[0041] In some embodiments, the first connection port 113 and the second connection port 21 are arranged opposite to each other in the length direction of the SEM objective lens 100. Figure 1 and Figure 2 As shown, the first connection port 113 and the second connection port 21 are arranged opposite to each other in the up-down direction, so that the aperture of the first aperture 3 and the aperture of the second aperture 4 are arranged opposite to each other.

[0042] Therefore, after the electron gun emits the electron beam, the electron beam can be emitted from the vacuum tube 9 through the first aperture 3 and the second aperture 4 in sequence to the internal space of the sample chamber, thereby ensuring that the center of each aperture hole can be aligned with the electron beam to avoid the negative impact of blocking the electron beam spot.

[0043] In some embodiments, the SEM objective lens 100 further includes a mounting bracket 6. Figure 2 As shown, the first end of the mounting bracket 6 is located in the first connection port 113, and the second end of the mounting bracket 6 is located in the second connection port 21. The mounting bracket 6 is a hollow structure, and as shown in FIG. Figure 1 As shown, the upper end of the mounting bracket 6 is fixedly installed in the first connection port 113 , and the lower end of the mounting bracket 6 is fixedly installed in the second connection port 21 .

[0044] The first aperture 3 is inserted through the first end of the mounting bracket 6, the second aperture 4 is inserted through the second end of the mounting bracket 6, and the middle part of the mounting bracket 6 has a communication port communicating with the interlayer cavity 14. Thus, the mounting bracket 6 can be used as a mounting support for the first aperture 3 and the second aperture 4, so that the relative positions of the first aperture 3 and the second aperture 4 in the scanning electron microscope objective 100 remain stable, and by providing the communication port, the space between the first aperture 3 and the second aperture 4 can be in a communicating state with the interlayer cavity 14, and then when the interlayer cavity 14 is evacuated, the space between the first aperture 3 and the second aperture 4 can form a vacuum difference with the tube cavity of the vacuum tube 9 and the internal space of the sample chamber, respectively.

[0045] In some embodiments, there are multiple communication ports, such as Figure 2 As shown, a plurality of connecting ports are spaced apart and distributed in the circumferential direction of the mounting bracket 6, so that the space between the first aperture 3 and the second aperture 4 can be connected to the interlayer cavity 14 through the plurality of connecting ports, thereby facilitating smooth and stable airflow in the interlayer cavity 14, and facilitating vacuuming of the interlayer cavity 14 and the space between the first aperture 3 and the second aperture 4.

[0046] In some embodiments, a sealing bushing 7 is disposed in the first connection port 113, and the sealing bushing 7 is sleeved outside the first end of the mounting bracket 6. Figure 2 As shown, the sealing bushing 7 is sleeved on the upper end of the mounting bracket 6 and abuts against the upper pole shoe 11 of the objective lens, and a portion of the sealing bushing 7 extends into the first hollow cavity 151 and is sleeved outside the lower end of the vacuum tube 9. That is, the outer peripheral wall of the sealing bushing 7 is relatively fixed to the inner peripheral wall of the first connecting port 113 of the upper pole shoe 11 of the objective lens, and the inner peripheral wall of the sealing bushing 7 is sealed with the mounting bracket 6 and the outer peripheral wall of the vacuum tube 9.

[0047] The bottom of the sealing bushing 7 is provided with intermittent grooves to correspond to the connecting opening of the mounting bracket 6, so as to improve the flow conductance and ensure the largest possible passage for the airflow.

[0048] In some embodiments, a support member 5 is provided between the end surface of one end of the sealing bushing 7 and the inner end surface of the lower pole shoe 2 of the objective lens. The support member 5 can be configured as a plurality of support claws, and the plurality of support claws can support the sealing bushing 7, so that the relative position of the sealing bushing 7 and the lower pole shoe 2 of the objective lens is fixed, thereby ensuring the sealing performance of the sealing bushing 7 at the first connection port 113.

[0049] According to the scanning electron microscope objective lens 100 of the embodiment of the present invention, a sandwich cavity 14 is formed by the matching design of the upper pole shoe assembly 1 of the objective lens and the lower pole shoe 2 of the objective lens, and an aperture is set at the outlet of the electron beam generating chamber, so that there is a pressure difference in the vacuum interlayer, thereby forming multiple vacuum interlayers with different pressure differences. A large vacuum gradient can be achieved between the sample chamber and the electron beam generating chamber, that is, when the vacuum in the sample chamber is ≤3000Pa, the vacuum at the electron gun is better than 9e-3Pa, and the excellent vacuum conditions required for electron beam emission are still available. It is perfectly compatible with low-vacuum secondary electron detectors and backscatter detectors, and within a certain working distance range, it effectively reduces the probability of collision between the initial electrons and the gas in the sample chamber on the emission path, improves the image signal-to-noise ratio under low vacuum, and the scanning electron microscope objective lens 100 of the embodiment of the present invention has a simple structure, requires less supporting equipment, is easy to implement, and is conducive to cost control.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" 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 representation of the above terms does 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.

[0051] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A scanning electron microscope objective lens, characterized in that: include: An objective lens upper pole shoe assembly (1), the objective lens upper pole shoe assembly (1) comprising a hollow cavity (15) and a first connection port (113), a vacuum tube (9) being arranged in the hollow cavity (15), the vacuum tube (9) being used to communicate with an electron beam generating chamber, and an end of the vacuum tube (9) extending to the first connection port (113), the first connection port (113) being provided with a first aperture (3); An objective lens lower pole shoe (2), the objective lens lower pole shoe (2) being provided with a second connection port (21), the second connection port (21) being used to communicate with the internal space of the sample chamber, the second connection port (21) being provided with a second diaphragm (4); An interlayer cavity (14) is formed between the objective lens upper pole shoe assembly (1) and the objective lens lower pole shoe (2), the first diaphragm (3) and the second diaphragm (4) are both provided with diaphragm holes communicating with the interlayer cavity (14), and the interlayer cavity (14) has a vacuum port (13).

2. The scanning electron microscope objective lens according to claim 1, characterized in that: The objective lens upper pole shoe assembly (1) comprises an objective lens upper pole shoe (11) and a vacuum connection cavity (12); the objective lens upper pole shoe (11) is connected to the objective lens lower pole shoe (2); the vacuum connection cavity (12) is connected to an end of the objective lens upper pole shoe (11) away from the objective lens lower pole shoe (2); the vacuum port (13) is arranged on the vacuum connection cavity (12); and the first connection port (113) is arranged on the objective lens upper pole shoe (11).

3. The scanning electron microscope objective lens according to claim 2, characterized in that: The objective lens upper pole shoe (11) comprises an inner layer part (111) and an outer layer part (112), wherein the outer layer part (112) is sleeved outside one end of the inner layer part (111), and the objective lens lower pole shoe (2) is sleeved outside the other end of the inner layer part (111) and connected to the outer layer part (112); The interlayer cavity (14) comprises a first sub-cavity (141), an intermediate sub-cavity (142) and a second sub-cavity (143); the first sub-cavity (141) is formed in the vacuum connection cavity (12); the intermediate sub-cavity (142) is formed between the inner layer part (111) and the outer layer part (112); and the second sub-cavity (143) is formed between the inner layer part (111) and the lower pole shoe (2) of the objective lens.

4. The scanning electron microscope objective lens according to claim 3, characterized in that: The hollow cavity (15) comprises a first hollow cavity (151) located in the inner layer part (111) and a second hollow cavity (152) located in the vacuum connection cavity body (12); the first connection port (113) is connected to the first hollow cavity (151); the second hollow cavity (152) is connected to an end of the first hollow cavity (151) facing away from the first connection port (113); and an end of the second hollow cavity (152) facing away from the first hollow cavity (151) is connected to an external space of the sample chamber.

5. The scanning electron microscope objective lens according to claim 3, characterized in that: The outer peripheral wall of the outer layer part (112) is provided with a mounting protrusion (1121), and the mounting protrusion (1121) is used to be connected to the peripheral wall of the sample chamber.

6. The scanning electron microscope objective lens according to claim 1, characterized in that: The first connection port (113) and the second connection port (21) are arranged opposite to each other in the length direction of the scanning electron microscope objective lens.

7. The scanning electron microscope objective lens according to claim 6, characterized in that: Also includes: A mounting bracket (6), wherein a first end of the mounting bracket (6) is located in the first connection port (113), and a second end of the mounting bracket (6) is located in the second connection port (21); The first diaphragm (3) is disposed through the first end of the mounting bracket (6), the second diaphragm (4) is disposed through the second end of the mounting bracket (6), and the middle portion of the mounting bracket (6) has a communication opening that communicates with the interlayer cavity (14).

8. The scanning electron microscope objective lens according to claim 7, characterized in that: There are a plurality of communication openings, and the plurality of communication openings are distributed at intervals in the circumferential direction of the mounting bracket (6).

9. The scanning electron microscope objective lens according to claim 7, characterized in that: A sealing bushing (7) is arranged in the first connection port (113), and the sealing bushing (7) is sleeved outside the first end of the mounting bracket (6).

10. The scanning electron microscope objective lens according to claim 9, characterized in that: A support member (5) is provided between the end surface of one end of the sealing bushing (7) and the inner end surface of the lower pole shoe (2) of the objective lens.

Images