WO2022246895A1

WO2022246895A1 - Centering mechanism and scanning electron microscope comprising same

Info

Publication number: WO2022246895A1
Application number: PCT/CN2021/098305
Authority: WO
Inventors: 李帅辰; 孟庆浪; 蒋磊; 孙伟强; 蒋俊海
Original assignee: 中科晶源微电子技术（北京）有限公司
Priority date: 2021-05-27
Filing date: 2021-06-04
Publication date: 2022-12-01
Also published as: CN116092903A

Abstract

The present application relates to a centering mechanism and a scanning electron microscope comprising same. The centering mechanism comprises an electron gun cavity and a mounting cavity that are successively and detachably connected; the electron gun cavity is provided with a first through hole, a first boss is provided on the side of the electron gun cavity facing the mounting cavity, and the first boss is of an annular structure around the first through hole; a mounting groove is provided on the side of the mounting cavity facing the electron gun cavity, the first boss is placed inside the mounting groove, and a distance is formed between the outer side wall of the first boss and the inner side wall of the mounting groove; a mounting hole is formed in the bottom of the mounting groove, the mounting hole passes through the mounting cavity, and a stigmator is mounted at the mounting hole; first adjusting members are movably mounted on the side wall, provided with the mounting groove, of the mounting cavity, the first adjusting members pass through the side wall of the mounting cavity, the number of the first adjusting members is greater than one, and multiple first adjusting members are distributed at intervals along the circumferential direction of the mounting groove. Thus, the center of an electric field of the stigmator coincides with the center of an optical axis, thereby implementing centering of the stigmator.

Description

Centering mechanism and scanning electron microscope with it

technical field

The present application relates to the field of semiconductors, in particular to a centering mechanism and a scanning electron microscope having the same.

Background technique

With the development of semiconductor technology and the advancement of process technology, the line width of integrated circuits is becoming more and more miniaturized, and higher and rarer requirements are placed on the production process technology of circuits. Not only must sub-micron lines be etched, but line defects are also eliminated It should be controlled within a certain range to ensure the function and yield of the chip. Studies have shown that when the size of the defect is more than one-third of the characteristic line width, it becomes a fatal defect and causes device failure. As the size of the device continues to shrink, the size of the fatal defect becomes smaller and smaller, and the detection of the defect becomes more difficult. The optical inspection equipment can no longer meet the needs, and the electron beam inspection equipment overcomes the limitation of the optical wavelength, making the resolution Increased to the nanometer field, tiny defects can be detected. The core of the electron beam detection equipment is the scanning electron microscope. Among them, the stigmator is an important device in the scanning electron microscope. As the name implies, its function is to eliminate phase dispersion. . Among them, the uniformity of the electrostatic field of the electrostatic stigmator is more difficult to control, and the alignment between the stigmator and the optical axis is difficult to grasp.

Contents of the invention

In view of this, the present application proposes a centering mechanism and a scanning electron microscope having the centering mechanism, which makes the center of the electric field of the stigmatizer coincide with the center of the optical axis, thereby realizing the centering of the stigmatizer.

According to one aspect of the present application, a centering mechanism is provided, which is used to be installed in a scanning electron microscope, and to adjust the relative relationship between the electric field center and the optical axis center of the stigmator in the scanning electron microscope, including sequentially Disassemble the connected electron gun cavity and installation cavity;

A first through hole is opened on the electron gun cavity, and a first boss is provided on a side of the electron gun cavity facing the installation cavity, and the first boss is arranged around the first through hole. ring structure;

The side of the installation cavity facing the electron gun cavity is provided with an installation groove, the first boss is placed inside the installation groove, the outer side wall of the first boss and the inner side wall of the installation groove with a distance between;

An installation hole is provided at the bottom of the installation groove, the installation hole is set through the installation cavity, and the installation hole is suitable for installing the stigmatizer;

On the side wall of the installation cavity where the installation groove is opened, a first adjustment member is installed on the side wall, the first adjustment member is arranged through the side wall of the installation cavity, and the first adjustment member is used to push the The first boss moves in the installation groove;

There are a plurality of first adjusting members, and the plurality of first adjusting members are distributed at intervals along the circumference of the installation groove.

In a possible implementation manner, the first boss includes an inclined portion, the side wall of the inclined portion is arranged on an inclined plane, the inclined portion is arranged adjacent to the groove bottom of the installation groove, and the inclined portion and the The distance between the inner side walls of the installation groove gradually decreases along the first direction;

Wherein, the first direction is a direction in which the electron gun cavity points to the installation cavity;

A plurality of the first adjustment members all abut against the inclined portion.

In a possible implementation manner, the first adjusting member is rod-shaped, and an external thread is provided on the rod of the first adjusting member;

The side wall of the installation cavity where the installation groove is opened is provided with a first internally threaded hole, the number of the first internally threaded hole is the same as the number of the first adjustment member, and the first adjustment member is the same as the first adjustment member. The first internally threaded holes are screwed in one-to-one correspondence.

In a possible implementation manner, the first boss further includes a connecting portion;

The connecting portion is arranged in an annular shape and is arranged circumferentially around the first through hole;

The bottom end surface of the connecting part is provided with an outer chamfer;

The inclined portion is fixed on the

On the side of the bottom end face of the connecting part, the top end face of the inclined part matches the bottom end face of the connecting part;

Wherein, the bottom of the connecting portion is a groove bottom side of the connecting portion adjacent to the installation groove.

In a possible implementation manner, a first sealing ring is also included;

There is a first sealing groove at the groove bottom of the installation groove, the first sealing groove is arranged in an annular shape, the first sealing groove is opposite to the first boss, and the first sealing groove surrounds the The circumferential setting of the first through hole;

The first sealing ring is installed in the first sealing groove for sealing the electron gun cavity and the installation cavity.

In a possible implementation manner, there is a gap between the side of the first boss facing the bottom of the installation groove and the bottom of the installation groove;

The first sealing ring abuts against the first boss.

In a possible implementation manner, it also includes an objective lens cavity, and the objective lens cavity is detachably mounted on a side of the installation cavity away from the electron gun cavity;

The objective lens cavity is provided with a second through hole coaxially arranged with the first through hole, and the objective lens cavity is provided with a placement groove toward one end of the installation cavity;

The installation cavity is provided with a second boss on the side facing the placement groove, the second boss is placed in the placement groove, the outer side wall of the second boss is connected to the inner side of the placement groove a distance is provided between the walls;

The objective lens cavity is provided with a second adjustment piece that is movably installed on the side wall of the place where the placement groove is located, and the second adjustment piece is provided with a plurality of the second adjustment pieces along the circumferential direction of the placement groove. interval distribution;

A plurality of the second adjusting members are all disposed through the side wall of the placing groove, and are used for pushing the second boss to move in the placing groove.

In a possible implementation manner, a second sealing ring is also included;

There is a second sealing groove at the bottom of the placement groove, the second sealing groove is arranged in an annular shape, the second sealing groove is opposite to the second boss, and the second sealing groove surrounds the second boss. The circumferential setting of the second through hole;

The second sealing ring is installed in the second sealing groove for sealing the installation cavity and the objective lens cavity.

In a possible implementation manner, there is a gap between the side of the second boss facing the placement groove and the placement groove;

The second sealing ring abuts against the second boss;

The structure of the second boss is the same as that of the first boss.

In a possible implementation manner, the mounting hole is in the shape of a stepped hole, and a diameter of a top of the mounting hole is larger than a diameter of a bottom of the mounting hole.

According to another aspect of the present application, a scanning electron microscope is provided, including a stigmator and the centering mechanism described in any one of the above;

Wherein, the stigmatizer is fixedly installed on the installation hole of the centering mechanism.

The centering mechanism of the embodiment of the present application is divided into two parts, the electron gun cavity and the installation cavity, wherein the installation cavity is detachably mounted on the bottom of the electron gun cavity, and the installation cavity is provided with a mounting hole for installing the stigmatizer. After the assembly of the electron gun cavity, the installation cavity and the stigmator is completed, at this time, the first boss at the bottom of the electron gun cavity is located in the installation groove. When the stigmatizer is centered with the optical axis, adjust the multiple first adjustment parts on the installation cavity, the length of the first adjustment parts protruding into the installation groove will change, so the movement of the first adjustment parts will push the first A boss moves in the installation groove, thereby driving the whole electron gun cavity to move and adjust. Since the first adjusting member is arranged in multiples along the circumference of the installation groove, the first adjusting member can adjust the position of the electron gun cavity in various directions until the stigmator on the installation cavity is aligned with the optical axis. To sum up, the centering mechanism of the embodiment of the present application drives the electron gun cavity to make fine adjustments in the installation groove by adjusting the first adjustment member, so that the center of the electric field of the stigmatizer coincides with the center of the optical axis, thereby realizing the Centering, thereby achieving the best state of the scanning electron microscope, reducing the impact of optical axis offset on the resolution and key parameters of the machine.

Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the application and, together with the specification, serve to explain the principles of the application.

Fig. 1 shows the explosion composition of the centering mechanism of the embodiment of the present application;

Figure 2 shows a partial enlarged view of the centering mechanism of the embodiment of the present application;

Figure 3 shows a partial enlarged view of the centering mechanism of the embodiment of the present application;

Fig. 4 shows the sectional view of the centering mechanism of the embodiment of the present application;

Fig. 5 shows a partially enlarged view of the assembly drawing of the electron gun cavity, the installation cavity and the objective lens cavity of the centering mechanism of the embodiment of the present application.

Detailed ways

Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numbers in the figures indicate functionally identical or similar elements. While various aspects of the embodiments are shown in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

Wherein, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "upper", "lower", "front", "rear", "left", "right" ", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", "Radial", "Circumferential ” and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention or simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, with a specific configuration and operation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or better than other embodiments.

In addition, in order to better illustrate the present application, numerous specific details are given in the following specific implementation manners. It will be understood by those skilled in the art that the present application may be practiced without certain of the specific details. In some instances, methods, means, components and circuits well known to those skilled in the art have not been described in detail in order to highlight the gist of the present application.

Fig. 1 shows an exploded view of the centering mechanism of the embodiment of the present application. As shown in Figure 1, the centering mechanism is used to be installed in the scanning electron microscope to adjust the relative positional relationship between the electric field center and the optical axis center of the stigmatizer 400 in the scanning electron microscope. The centering mechanism includes: The connected electron gun cavity 100 and installation cavity 200 are disassembled, wherein the electron gun cavity 100 can be installed with components such as an electron gun and a condenser. The electron gun cavity 100 is provided with a first through hole, and the side of the electron gun cavity 100 facing the installation cavity 200 is provided with a first boss 110, the first boss 110 is in a ring structure, and the first boss 110 is wound around The first through holes are arranged circumferentially. The side of the installation cavity 200 facing the electron gun cavity 100 is provided with an installation groove. When the electron gun cavity 100 and the installation cavity 200 are assembled, the first boss 110 is located inside the installation groove, and the outer side wall of the first boss 110 There is a distance from the inner side wall of the installation groove (and the first boss 110 can fit in clearance with the installation groove). A mounting hole is provided at the bottom of the mounting groove, the mounting hole is set through the mounting cavity 200 , and the mounting hole is used for mounting the stigmatizer 400 . The first adjusting member 300 is movably installed on the side wall of the installation cavity 200 where the installation groove is opened, and there are multiple first adjusting members 300, and the plurality of first adjusting members 300 are distributed along the circumferential direction of the installation groove at intervals, and each Each of the first adjusting members 300 is provided through the side wall of the installation cavity 200, and is used to push the first boss 110 (and the electron gun cavity 100) to move in the installation groove.

The centering mechanism of the embodiment of the present application is divided into two parts: the electron gun cavity 100 and the installation cavity 200, wherein the installation cavity 200 is detachably installed at the bottom of the electron gun cavity 100, and the installation cavity 200 is provided with an installation stigmatizer 400 the mounting holes. After the assembly of the electron gun cavity 100 , the installation cavity 200 and the stigmatizer 400 is completed, at this time, the first boss 110 at the bottom of the electron gun cavity 100 is located in the installation groove. When the stigmatizer 400 is centered with the optical axis, adjust the multiple first adjustment parts 300 on the installation cavity 200, the length of the first adjustment parts 300 extending into the installation groove will change, so the first adjustment parts 300 The movement of the first boss 110 will push the first boss 110 to move in the installation groove, thereby driving the entire electron gun cavity 100 to move and adjust. Since the first adjusting member 300 is arranged in multiples along the circumferential direction of the installation groove, the first adjusting member 300 can adjust the position of the electron gun cavity 100 in various directions until the stigmatizer 400 on the installation cavity 200 is aligned with the The optical axis is centered. To sum up, the centering mechanism of the embodiment of the present application drives the electron gun cavity 100 to make fine adjustments in the installation groove by adjusting the first adjustment member 300, so that the center of the electric field of the stigmator 400 coincides with the center of the optical axis, thereby realizing image elimination The centering of the diffuser 400, thereby achieving the best state of the scanning electron microscope, reducing the impact of the optical axis offset on the resolution and key parameters of the machine.

Here, it should be noted that, in a possible implementation manner, the electron gun cavity 100 is cylindrical, and the axis of the first through hole coincides with the axis of the electron gun cavity 100. Thus, the alignment between the stigmator 400 and the optical axis is further facilitated, and the structure of the embodiment of the present application is optimized.

Here, it should also be pointed out that in a possible implementation manner, the installation cavity 200 is cylindrical, and after the assembly of the installation cavity 200 and the electron gun cavity 100 is completed, the outer wall of the installation cavity 200 and the electron gun cavity The outer side wall of 100 is set flush. The mounting groove is in the shape of a circular groove, and the axis of the mounting groove coincides with the axis of the first through hole, and the axis of the mounting hole coincides with the axis of the first through hole. Thus, it is easier to align the stigmator 400 with the optical axis, and the alignment is more accurate.

Here, it should also be pointed out that in a possible implementation, the top end surface of the installation cavity 200 is arranged parallel to the bottom end surface of the electron gun cavity 100, and after the electron gun cavity 100 and the installation cavity 200 are assembled, The bottom flat end surface of the electron gun cavity 100 is arranged in abutment with the top end surface of the installation cavity 200 . The mounting holes include a first hole and a second hole arranged sequentially in a stepped shape, wherein the first hole is arranged adjacent to the electron gun cavity 100 , and the bottom end surface of the first hole is parallel to the top end surface of the installation cavity 200 . Thus, the parallelism of the contact surface of the electron gun cavity 100 and the installation cavity 200 is improved, and the parallelism of the contact surface of the installation cavity 200 and the stigmatizer 400 is also improved, the shape and position tolerance is reduced, and light Shaft offset reduces installation errors.

As shown in FIG. 1 , FIG. 2 or FIG. 4 , in a possible implementation, the first boss 110 includes an inclined portion 112 , the side wall of the inclined portion 112 is arranged on an inclined plane, and the inclined portion 112 is adjacent to the groove bottom of the installation groove. It is provided that the distance between the inclined portion 112 and the inner side wall of the installation groove decreases gradually along the first direction. Wherein, the first direction is a direction in which the electron gun cavity points to the installation cavity 200 , and each first adjusting member 300 abuts against the inclined portion 112 . Since the first adjusting member 300 abuts against the first boss 110, and the force-receiving part of the first boss 110 is the inclined surface 112, when the first adjusting member 300 acts, it will exert a downward component force on the inclined surface 112, so that It will not tilt up during movement, which ensures the sealing effect.

Furthermore, in a possible implementation manner, the first boss 110 also includes a connecting portion 111, wherein the connecting portion 111 is arranged in a ring shape, and the connecting portion 111 is circumferentially arranged around the first through hole, and the bottom of the connecting portion 111 The end faces are provided with chamfers. The inclined portion 112 is fixed on one side of the bottom end surface of the connecting portion 111 , and the top end surface of the inclined portion 112 matches the bottom end surface of the connecting portion 111 . Wherein, the bottom of the above-mentioned connecting portion 111 is a groove bottom side of the connecting portion 111 adjacent to the installation groove. As a result, the structure of the first boss 110 is more matched with the structure of the first adjusting member 300, further preventing the first boss 110 from tilting during movement.

Here, it should be noted that, in a possible implementation manner, the connecting portion 111 , the inclined portion 112 and the electron gun cavity 100 may be integrally formed. This facilitates the manufacture of the electron gun cavity 100 .

In a possible implementation, a first sealing ring 500 is also included, and a first sealing groove is opened at the bottom of the installation groove, the first sealing groove is annular, and the first sealing groove is opposite to the first boss 110 It is provided that the first sealing groove is circumferentially arranged around the first through hole. The first sealing ring 500 is installed in the first sealing groove, and the first sealing ring 500 is used to seal the electron gun cavity 100 and the installation cavity 200 . Thus, the sealing performance of the electron gun cavity 100 and the installation cavity 200 is increased.

Furthermore, in a possible implementation, after the electron gun cavity 100 and the installation cavity 200 are assembled, there is a gap between the first boss 110 and the bottom of the installation groove, and the first sealing ring 500 and the second A boss 110 abuts against it. Thus, without affecting the sealing effect, it is avoided that the first boss 110 and the groove bottom of the installation groove are used as the contact surface, and the phenomenon that the tolerance of the sealing ring itself is uncertain is avoided, and the optical axis deviation is further placed. shift, reducing installation errors.

In a possible implementation manner, the first adjusting rod is rod-shaped, and an external thread is provided on the rod of the first adjusting member 300 . The installation cavity 200 is provided with a first internally threaded hole on the side wall where the installation groove is opened, and the number of the first internally threaded hole is the same as the number of the first adjusting member 300, and the first adjusting member 300 is the same as the first internally threaded hole. A corresponding screw connection. Therefore, the position of the electron gun cavity 100 can be adjusted by rotating the first adjusting member 300, so that the centering of the stigmator 400 and the optical axis is more convenient.

As shown in Figure 1, Figure 2, Figure 3 or Figure 4, further, in a possible implementation, it also includes an objective lens cavity 600, and the objective lens cavity 600 is detachably installed in the installation cavity 200 away from the electron gun cavity one side of the body 100. A second through hole coaxial with the first through hole is opened on the objective lens cavity 600 , and a placement slot is opened on the end of the objective lens cavity 600 facing the installation cavity 200 . The installation cavity 200 is provided with a second boss 210 on the side facing the placement groove. The second boss 210 is placed in the placement groove. There is a distance between the outer side wall of the second boss 210 and the inner side wall of the placement groove. A second adjusting member 700 is movably installed on the side wall of the objective lens cavity 600 where the placement groove is opened. There are multiple second adjusting members 700, and the plurality of second adjusting members 700 are distributed along the circumferential direction of the placement groove at intervals. A plurality of second adjusting members 700 are arranged through the side wall of the placement groove, and one end of the plurality of second adjusting members 700 facing the second boss 210 is connected to the second boss 210 for pushing the installation cavity 200 into the placement groove. move within. Through the above structure, the second adjusting member 700 is adjusted so that the second adjusting member 700 drives the second boss 210 to move in the placement groove, thereby, the position of the installation cavity 200 can be adjusted, so that the astigmatism on the installation cavity 200 can be eliminated. The device 400 is centered with the objective lens.

Here, it should be noted that, in a possible implementation, the second through hole is coaxially arranged with the first through hole, the objective lens cavity 600 is cylindrical, and the outer wall of the objective lens cavity 600 is in line with the mounting cavity 200. The outer wall is arranged flush, and the diameter of the second through hole is the same as that of the first through hole. Thus, the structure of the embodiment of the present application is further optimized.

Here, it should also be noted that, in a possible implementation manner, the side walls of the second boss 210 are arranged parallel to the side walls of the first boss 110 . The top end surface of the objective lens cavity 600 is arranged parallel to the bottom end surface of the installation cavity 200, and after the objective lens cavity 600 and the installation cavity 200 are assembled, the top end surface of the objective lens cavity 600 is overlapped with the bottom end surface of the installation cavity 200. The top end surface of the objective lens cavity 600 is arranged parallel to the bottom of the installation groove of the installation cavity 200 . This further eliminates the shape and position tolerance.

Here, it should also be noted that, in a possible implementation manner, the electron gun cavity 100 is provided with a plurality of first bolt holes, and the plurality of first bolt holes are all set through the electron gun cavity 100, and the plurality of first bolt holes A bolt hole is distributed around the axis of the electron gun cavity 100 , and a plurality of first bolt holes are arranged adjacent to the edge of the electron gun cavity 100 . The installation cavity 200 is provided with a plurality of second bolt holes, the number of the second bolt holes is the same as the number of the first bolt holes, and the second bolt holes are set in one-to-one correspondence with the first bolt holes, and the second bolt holes all penetrate The installation cavity 200 is provided. The objective lens cavity 600 is provided with a plurality of third bolt holes, the number of the third bolt holes is the same as the number of the first bolt holes, and the third bolt holes correspond to the first bolt holes one by one. The electronic cavity, the mounting cavity 200 and the objective lens cavity 600 are connected by bolts (the bolts are screwed into the first bolt hole, the second bolt hole and the third bolt hole in sequence). Therefore, after the electron gun cavity 100 and the installation cavity 200 are adjusted, they can be locked by bolts to prevent their movement and ensure that their relative positions will not change.

Furthermore, it also includes a second sealing ring 800, a second sealing groove is provided at the bottom of the groove, the second sealing groove is arranged in an annular shape, the second sealing groove is opposite to the prime number second boss 210, the second The sealing groove is circumferentially arranged around the second through hole. The second sealing ring 800 is installed in the second sealing groove for sealing the installation cavity 200 and the objective lens cavity 600.

In a possible implementation manner, there is a gap between the side of the second boss 210 facing the placement groove and the placement groove, and the second sealing ring 800 abuts against the second boss 210 . The structure of the second protrusion is the same as that of the first boss 110 . Thus, the second boss 210 (and the objective lens cavity 600 ) can be prevented from warping during the movement, so that the sealing performance is guaranteed.

In a possible implementation manner, the installation hole is in the shape of a stepped hole, and the diameter of the top hole of the installation hole is larger than the diameter of the bottom hole of the installation hole. By setting the installation hole as a stepped hole, an installation location is provided for the stigmatizer 400 . Here, it should also be noted that the stigmatizer 400 is completely placed in the installation hole.

As shown in FIG. 1 or FIG. 5 , based on the centering mechanism described in any one of the above, the present disclosure also provides a scanning electron microscope. Wherein, the scanning electron microscope of the embodiment of the present disclosure includes the centering mechanism and the stigmator 400 described above. Wherein, the stigmatizer 400 is fixedly installed on the mounting hole of the centering mechanism, and any of the aforementioned centering mechanisms is installed on the scanning electron microscope, thereby facilitating the alignment between the stigmatizer 400 and the optical axis Alignment. Wherein, an electron gun and a condenser lens can be installed on the electron gun cavity 100 , and an objective diaphragm, a detector, an objective lens and a deflector can be installed on the objective lens cavity 600 .

Here, it should be noted that, in a possible implementation manner, the stigmator 400 may include a base 410 and an electrode plate 420 , the base 410 is in the shape of a hollow cylinder, and the base 410 is used to be fixedly installed on a centering mechanism. There are multiple pole plates 420, and the multiple pole plates 420 are arranged in the hollow of the base 410. The multiple pole plates 420 are arranged in sequence around the inner wall of the base 410, and the multiple pole plates 420 are fixedly connected to the bottom plate. One ends of the plurality of pole plates 420 protrude from the base 410 . Therefore, by providing multiple pole plates 420 , multiple sets of pole plates 420 are arranged in a ring structure arranged in sequence around the inner wall of the base 410 , thereby making the alignment between the stigmatizer 400 and the optical axis more convenient.

Here, it should be noted that, in a possible implementation manner, the base 410 is cylindrical, and a baffle is disposed on one end surface of the base 410 , and the baffle is circumferentially disposed around the outer wall of the base 410 . A plurality of fixing holes are opened on the baffle for fixing the stigmator 400 on the installation cavity.

Here, it should also be noted that, in a possible implementation manner, the pole plate 420 includes a protruding portion 412 and a fixing portion 411 , wherein the fixing portion 411 is in the shape of an arc plate matching the inner wall of the bottom plate. The end surface of the fixed portion 411 adjacent to the baffle is flush with the baffle, and the protruding portion 412 is fixed on the end surface of the fixed portion 411 adjacent to the baffle. The protruding plate is arc-shaped, and the end surface area of the protruding portion 412 is larger than that of the fixing portion 411 , so that the protruding portion 412 is arranged in contact with the baffle. Here, it should also be noted that the side of the fixing portion 411 facing the axis of the base 410 is arranged flush with the side of the protruding portion 412 facing the axis of the base 410 . Thus, the structure of the stigmator 400 in the embodiment of the present application is optimized.

Having described various embodiments of the present application above, the foregoing description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and alterations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principle of each embodiment, practical application or improvement of technology in the market, or to enable other ordinary skilled in the art to understand each embodiment disclosed herein.

Claims

A centering mechanism, characterized in that it is used to be installed in a scanning electron microscope to adjust the relative relationship between the electric field center and the optical axis center of the stigmatizer in the scanning electron microscope, including electron gun chambers that are detachably connected in turn Body and installation cavity;

A first through hole is opened on the electron gun cavity, and a first boss is provided on a side of the electron gun cavity facing the installation cavity, and the first boss is arranged around the first through hole. Ring structure;

The side of the installation cavity facing the electron gun cavity is provided with an installation groove, the first boss is placed inside the installation groove, the outer side wall of the first boss and the inner side wall of the installation groove with a distance between;

An installation hole is provided at the bottom of the installation groove, the installation hole is set through the installation cavity, and the installation hole is suitable for installing the stigmatizer;

On the side wall of the installation cavity where the installation groove is opened, a first adjustment member is installed on the side wall, the first adjustment member is arranged through the side wall of the installation cavity, and the first adjustment member is used to push the The first boss moves in the installation groove;

There are a plurality of first adjusting members, and the plurality of first adjusting members are distributed at intervals along the circumference of the installation groove.
The centering mechanism according to claim 1, wherein the first boss includes a slope, the side wall of the slope is arranged on a slope, and the slope is arranged adjacent to the groove bottom of the installation groove, The distance between the inclined portion and the inner side wall of the installation groove gradually decreases along the first direction;

Wherein, the first direction is a direction in which the electron gun cavity points to the installation cavity;

A plurality of the first adjustment members all abut against the inclined portion.
The centering mechanism according to claim 1, wherein the first adjusting member is rod-shaped, and the rod of the first adjusting member is provided with external threads;

The side wall of the installation cavity where the installation groove is opened is provided with a first internally threaded hole, the number of the first internally threaded hole is the same as the number of the first adjustment member, and the first adjustment member is the same as the first adjustment member. The first internally threaded holes are screwed in one-to-one correspondence.
The centering mechanism according to claim 2, wherein the first boss further includes a connecting portion;

The connecting portion is arranged in an annular shape and is arranged circumferentially around the first through hole;

The bottom end surface of the connecting part is provided with an outer chamfer;

The inclined portion is fixed on the

On the side of the bottom end face of the connecting part, the top end face of the inclined part matches the bottom end face of the connecting part;

Wherein, the bottom of the connecting portion is a groove bottom side of the connecting portion adjacent to the installation groove.
The centering mechanism according to claim 1, further comprising a first sealing ring;

There is a first sealing groove at the groove bottom of the installation groove, the first sealing groove is arranged in an annular shape, the first sealing groove is opposite to the first boss, and the first sealing groove surrounds the The circumferential setting of the first through hole;

The first sealing ring is installed in the first sealing groove for sealing the electron gun cavity and the installation cavity.
The centering mechanism according to claim 5, wherein a gap is provided between the side of the first boss facing the bottom of the installation groove and the bottom of the installation groove;

The first sealing ring abuts against the first boss.
The centering mechanism according to any one of claims 1 to 6, further comprising an objective lens cavity, the objective lens cavity is detachably installed on the side of the installation cavity away from the electron gun cavity;

The objective lens cavity is provided with a second through hole coaxially arranged with the first through hole, and the objective lens cavity is provided with a placement groove toward one end of the installation cavity;

The installation cavity is provided with a second boss on the side facing the placement groove, the second boss is placed in the placement groove, the outer side wall of the second boss is connected to the inner side of the placement groove a distance is provided between the walls;

The objective lens cavity is provided with a second adjustment piece that is movably installed on the side wall of the place where the placement groove is located, and the second adjustment piece is provided with a plurality of the second adjustment pieces along the circumferential direction of the placement groove. interval distribution;

A plurality of the second adjusting members are all disposed through the side wall of the placing groove, and are used for pushing the second boss to move in the placing groove.
The centering mechanism according to claim 7, further comprising a second sealing ring;

There is a second sealing groove at the bottom of the placement groove, the second sealing groove is arranged in an annular shape, the second sealing groove is opposite to the second boss, and the second sealing groove surrounds the second boss. The circumferential setting of the second through hole;

The second sealing ring is installed in the second sealing groove for sealing the installation cavity and the objective lens cavity.
The centering mechanism according to claim 8, wherein a gap is provided between the side of the second boss facing the placement groove and the placement groove;

The second sealing ring abuts against the second boss;

The structure of the second boss is the same as that of the first boss.
The centering mechanism according to claim 1, wherein the installation hole is in the shape of a stepped hole, and the diameter of the top of the installation hole is larger than the diameter of the bottom of the installation hole.
A scanning electron microscope, characterized in that it comprises a stigmator and the centering mechanism described in any one of claims 1 to 10;

Wherein, the stigmatizer is fixedly installed on the installation hole of the centering mechanism.