WO2021120547A1

WO2021120547A1 - Scanning electron microscope sample table equipped with dual manipulators

Info

Publication number: WO2021120547A1
Application number: PCT/CN2020/095356
Authority: WO
Inventors: 陈科纶; 卢海洋; 孙钰; 汝长海; 朱军辉
Original assignee: 江苏集萃微纳自动化系统与装备技术研究所有限公司
Priority date: 2019-12-20
Filing date: 2020-06-10
Publication date: 2021-06-24
Also published as: CN110896018A; CN110896018B

Abstract

Disclosed is a scanning electron microscope sample table equipped with dual manipulators, the table comprising a sample cup. Two nano-operation manipulators are symmetrically arranged in the sample cup, and the two nano-operation manipulators collaboratively cooperate to achieve a variety of operations. The present invention is applicable to Phenom tabletop electron microscopes, and can implement various complex motions and functions under a microscope, such as the electrical measuring of multiple contacts, material feature detection, nano-scale multi-point positioning and accurate positioning, and the like. The structure thereof is compact, the design is clever, and the table makes breakthroughs in terms of having multi-varied functions, a micro-space sample table design, manipulator stability, positioning accuracy, etc.

Description

Scanning electron microscope sample stage with dual manipulators

Technical field

The invention relates to the technical field of scanning electron microscopes, in particular to a scanning electron microscope sample stage with dual manipulators.

Background technique

Scanning electron microscope is widely used in materials science, electronics, medical and physics and other fields, and it has become an important tool for people to observe and study small objects. It uses the principle of electron beam imaging to observe tiny objects that cannot be seen by traditional optical microscopes. At the same time, how to design a scanning electron microscope that is simple to use, convenient and fast has become a problem for the development of the industry.

The European patent number EP2024750B1 discloses a compact scanning electron microscope, which is portable and simple to operate. This compact scanning electron microscope uses a specially designed sample stage, which is shaped like a cup. The sample is placed in the cup, and then air is drawn out of the cup, creating a vacuum environment for electronic imaging. Due to the limited power of the air pump, in order to discharge air better and faster, the sample stage usually requires a relatively small volume, which reduces the user's time for changing samples and waiting for vacuum.

Phenom Desktop Electron Microscope offers a variety of sample stages. It can image samples of different shapes, sizes and properties. The function is limited to pure imaging and analysis (such as EDX). Compared with accessories on traditional large scanning electron microscopes, desktop SEMs are limited in function due to their strict space constraints. But as people's demand for various information about samples continues to increase, people are not only satisfied with static or single-screen sample information.

Summary of the invention

The technical problem to be solved by the present invention is to provide a scanning electron microscope sample stage with dual manipulators, which has diverse functions, compact structure and space saving.

In order to solve the above technical problems, the present invention provides a scanning electron microscope sample stage with dual manipulators, including a sample cup in which two nanomanipulation manipulators are symmetrically arranged.

Preferably, the single nano manipulator includes a first linear drive assembly located on the top, and the first linear drive assembly includes an X-direction macro-motion linear drive module and a Y-direction macro-motion linear drive module.

Preferably, the X-direction macro-motion linear drive module is located on the upper side of the Y-direction macro-motion linear drive module or the Y-direction macro-motion linear drive module is located on the upper side of the X-direction macro-motion linear drive module.

Preferably, it further includes a second linear drive assembly, the second linear drive assembly is located on the lower side of the first linear drive assembly; the second linear drive assembly includes a Z-direction macro-motion drive stacked in series in the vertical direction Module, X-direction micro-motion linear drive module, Y-direction micro-motion linear drive module and Z-direction micro-motion drive module.

Preferably, the X-direction macro-motion linear drive module, the Y-direction macro-motion linear drive module and the Z-direction macro-motion drive module all include a macro-motion linear guide drive with stick-slip drive.

Preferably, the X-direction micro-motion linear drive module, the Y-direction micro-motion linear drive module and the Z-direction micro-motion drive module all include micro-motion linear drives driven by piezoelectric ceramics.

Preferably, the nano-manipulation manipulator is a multi-degree-of-freedom manipulator.

Preferably, it also includes a mechanical claw assembly for operating the sample, and the mechanical claw assembly is detachably connected to the nano-manipulation manipulator.

Preferably, the nano-manipulator is provided with a multi-pin socket, and the mechanical claw assembly is provided with a multi-pin plug matched with the socket.

Preferably, the mechanical claw assembly is a probe, a probe with a sensor or a mechanical clamping claw.

The beneficial effects of the present invention:

In the present invention, two nano-manipulators are symmetrically arranged in the sample cup. On the one hand, the two nano-manipulators can cooperate and cooperate to realize the pickup and placement of micro-nano objects; on the other hand, two probes are installed on the nano-manipulator. To make electrical contact with the sample to achieve electrical measurement; alternatively, mechanical claws can be installed on the nano-manipulator to stretch nano-materials. Such difficult movements can be achieved by the coordinated action of the dual-manipulators in the present invention. . In this way, the function of the desktop electron microscope is no longer limited to pure imaging and analysis, but can meet a variety of needs, with diverse functions, and due to the symmetrical arrangement of two nano-manipulators, its structure is more compact and space-saving.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the present invention;

Figure 2 is a schematic diagram of the structure with the sample cup removed.

Explanation of reference numerals in the figure: 10, sample cup; 11, cover; 20, platform; 21, slider; 22, spring plunger; 30, drive circuit board; 40, Y-direction macro-motion linear drive module; 41, X-direction Macro motion linear drive module; 42, Z direction micro motion linear drive module; 43, Y direction micro motion linear drive module; 44, X direction micro motion linear drive module; 45, Z direction macro motion linear drive module; 50, mechanical claw Components; 51, sockets.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the examples cited are not intended to limit the present invention.

The invention discloses a scanning electron microscope sample table with dual manipulators, which comprises a sample cup, in which two nano-manipulation manipulators are symmetrically arranged. The sample cup in the present invention is suitable for the Phenom desktop electron microscope in the background art, and the sample cup is a Phenom sample cup, which is in the shape of a slender cup and has an outer diameter of only 44 mm. In the present invention, two nano-manipulators are symmetrically arranged in the sample cup. On the one hand, the two nano-manipulators can cooperate and cooperate to realize the pickup and placement of micro-nano objects; on the other hand, two probes are installed on the nano-manipulator. To make electrical contact with the sample to achieve electrical measurement; alternatively, mechanical claws can also be installed on the nanomanipulator to stretch the nanomaterial. Such highly difficult actions can be realized only by using the coordinated action of the dual manipulators in the present invention. In this way, the function of the desktop electron microscope is no longer limited to pure imaging and analysis, and can meet a variety of needs. And because the two nano-manipulators are symmetrically arranged, the structure is more compact and space saving.

As we all know, the existing scanning electron microscope (SEM) has completely different requirements for sample placement and working environment from ordinary air environment. It is distinguished from optical microscopes by electron beam imaging. We need to place the sample in a vacuum non-magnetic cavity to avoid magnetic field or air and other media from interfering with the movement of the electron beam. Therefore, when people want to add a movable manipulator to the SEM, they need to make a larger change in the design of the manipulator than usual. These changes include the need to abandon the design of traditional manipulators: manipulators placed in a vacuum must not be magnetic, and we cannot use any ordinary robots or motors used by manipulators and other driving methods, because the driving principle of the motor includes magnetic fields and coils; all materials are It needs vacuum compatibility, so we can't use the steel and iron magnetic materials used by ordinary robots or manipulators. Obviously, this change has caused the integrated manipulator in SEM to become a brand new problem, and it should involve a brand new field that is different from ordinary manipulators. Such a manipulator is not only a "mini version" of an ordinary manipulator, but also a manipulator or robot with new drives and materials. The compact scanning electron microscope sample stage with a dual-manipulator structure that we have proposed is completely proposed in this brand-new field. We use piezoelectric ceramics as the driving source, and all materials are vacuum compatible.

Since the magnetism of the guide rail affects the movement of the electron beam and thus the imaging of the SEM, when designing the nanomanipulator, the magnetic linear guide drive is as far away as possible from the sample and away from the imaging area. There are four nano-manipulators that we can find on the market that are well-known and have been made into products. We found that they all follow the above principles, and such principles and design methods are well known by people. At the same time, they also Solidified people's design of the manipulator. The nanomanipulator designed by Thermo Fisher adopts macro and micro drives. They place the macromotion linear guide drive away from the manipulator below the sample to avoid the influence of magnetism on SEM imaging; the nanomanipulator designed by Toronto nano instrumentation also uses The macro drive is similar to the Thermo Fisher company’s design. The macro motion linear guide drive is placed at the bottom of the manipulator; the nano manipulator proposed by SmarAct uses only the macro motion. They design all the macro motion linear guide drives away from the sample. Far away to avoid interference. The last Kleindiek is similar to SmarAct, with only Hongdong, and like all the companies mentioned above, the guide rail drive needs to be placed away from the sample table. Although such a design leads to a larger size of the manipulator, people have to design this way due to the limitations of SEM imaging.

However, we found that Phenom’s desktop electron microscope, because it uses a higher-energy backscattered electron imaging method, is different from the traditional SEM’s weaker energy secondary electron imaging method, and has higher resistance. Magnetic field interference. After experimental testing, we have verified this feature and verified that the interference of the Phenom desktop electron microscope by the macro motion linear guide drive is relatively small and can be ignored. The SEM can be used for normal imaging. Therefore, we are no longer limited to the design of the previous manipulators, and change the stacking position of the drivers to design a smaller manipulator.

In the present invention, a single nanomanipulator includes a first linear drive assembly on the top, and the first linear drive assembly includes an X-direction macro-motion linear drive module and a Y-direction macro-motion linear drive module. Among them, the X direction and the Y direction are arranged perpendicularly, and the plane where the X direction and the Y direction are located is a horizontal plane. The Z direction is set vertically. Since the first linear drive component is located at the top of the nanomanipulator, that is, roughly positioned at the top, all other drive stages are placed below. This structure minimizes the use of radial space, thus allowing two manipulators to be integrated in the simple sample cup of the electron microscope. Those skilled in the art know that during the movement of the manipulator, we cannot allow the manipulator to collide with the rest of the position. In order not to interfere with the movement, it is inevitable that we need to simulate the movement trajectory in advance. "Move away. Therefore, usually the manipulators we see have a large safe range of motion, and a large space is reserved to ensure the safety of motion. After a series of studies, we have found that "reserved space" is unnecessary in many cases. How to reduce the "reserved space" as little as possible through the mechanical design without changing the manipulator stroke, we have worked hard for a long time. Finally, in the nano-manipulation manipulator of the present invention, the guide rail in the XY direction that has the greatest impact on the radial space requirement is installed at the end of the manipulator, and the rest of the front end is as symmetrically stacked as possible, so that the lower part reduces XY as much as possible. The movement stroke in the direction can effectively reduce the reserved space required in the XY plane, so the sample cup of the manipulator can be made very "fine". Moreover, this design has its unique characteristics. This is because people usually don't put the coarse-moving XY-direction guide at the top, because the magnetism of the linear guide drive will affect the imaging of the scanning electron microscope. We have discovered that most of the detection signals used by phenom desktop electron microscopes are backscattered spot electrons (BSD), which have higher energy than secondary electron imaging (SED), and therefore have stronger resistance to magnetic interference. Therefore, for this kind of backscattered electron imaging phenom desktop electron microscope, under the premise of ensuring that it can meet the needs after installation, such a bold design has been made. Therefore, the XY motion part of the top is placed on the top, which can leave a considerable space for the manipulator to have a large enough range of motion. Therefore, the present invention solves the problem that multiple manipulators cannot be placed due to too small space.

The vertical stacking sequence of the X-direction macro-movement linear drive module red and Y-direction macro-movement linear drive module can be designed according to work requirements. The X direction macro motion linear drive module is located on the upper side of the Y direction macro motion linear drive module, or the Y direction macro motion linear drive module is located on the upper side of the X direction macro motion linear drive module.

The present invention also includes a second linear drive assembly, the second linear drive assembly is located on the lower side of the first linear drive assembly; the second linear drive assembly includes Z-direction macro-motion drive modules and X-direction micro-drive modules stacked in series in the vertical direction Linear drive module, Y-direction micro-motion linear drive module and Z-direction micro-motion drive module. The stacking sequence of the Z-direction macro-motion drive module, the X-direction micro-motion linear drive module, the Y-direction micro-motion linear drive module, and the Z-direction micro-motion drive module can be adjusted.

In an embodiment of the present invention, the X-direction macro-motion linear drive module and the Y-direction macro-motion linear drive module are installed at the end of the manipulator, and the remaining XYZ micro-movement and Z macro-movement parts are designed below it. Let the lower part reduce the movement stroke in the XY direction as much as possible, which can effectively reduce the reserved space required in the XY plane, which greatly reduces the interference caused by the other 4 driving processes except the XY macro motion. The large reserved space design in the XY plane reduces the required space. At the same time, the present invention designs the Z-direction macro-motion drive module at the bottom to ensure that the Z-direction macro-motion drive module with the largest mass is at the relatively lowest, that is, the most "stable" position, effectively reducing unnecessary vibration interference. At the same time, the two manipulators are stacked symmetrically, which can minimize the space for placing two manipulators at the same time.

The X-direction macro-motion linear drive module, the Y-direction macro-motion linear drive module and the Z-direction macro-motion drive module all include a macro-motion linear guide drive with stick-slip drive. The X-direction micro-motion linear drive module, the Y-direction micro-motion linear drive module and the Z-direction micro-motion drive module all include micro-motion linear drives driven by piezoelectric ceramics. The present invention includes the principle of macro and micro drive, and then combines the above-mentioned compact structure features. The so-called macro-micro drive idea here means that we divide the drive in each direction into macro-motion and micro-motion. Macro and micro drives play a very important role in the nanomanipulation in SEM. The so-called macro motion here refers to the large-scale long-distance movement controlled by the linear guide drive of the stick-slip drive. It is driven by piezoelectric ceramics. The rapid and instantaneous growth of piezoelectric ceramics and the huge driving force generated instantly exceed the friction of the guide rail and friction. The bonding force of the sheet causes relative sliding of the surface, and then the relative movement is stopped due to the bonding of the surface again. The high-frequency vibration of piezoelectric ceramics superimposes each relative sliding to obtain a larger relative motion, which we define as macro motion. The so-called fretting here refers to that the piezoelectric ceramic is used to precisely control the voltage applied to both ends of the piezoelectric ceramic during one expansion process, so that the hinge driven by the piezoelectric ceramic obtains a small displacement with very good repeatability. Such a small displacement has no friction, good repeatability, and high positioning accuracy. We call it micro-motion. The traditional nano-manipulation manipulator does not use the principle of macro and micro drive. To ensure the motion stroke of the manipulator, it can only adopt a larger macro motion drive mode. Such a manipulator will have a fatal problem in the process of moving-the end of the manipulator shakes. This is caused by the stick-slip drive characteristics of the macromotion guide linear drive. We can clearly see such "jitter" in the SEM. Therefore, when we move the manipulator, it is easy for the manipulator to be unable to grasp the nanomaterials and even damage some surrounding things. Therefore, it is very necessary to adopt macro and micro drives, and the stability of the nano manipulator in the present invention is better.

The nanomanipulator is a multi-degree-of-freedom manipulator.

The invention also includes a mechanical claw assembly for operating the sample, and the mechanical claw assembly is detachably connected to the nano-manipulation manipulator. In another embodiment, the nano-manipulator is provided with a multi-pin socket, and the mechanical claw assembly is provided with a multi-pin plug that matches with the socket. In this way, the nano-manipulator and the mechanical claw assembly can be detachably connected, which is convenient Replace the mechanical jaw assembly to achieve different operations. Multi-pin sockets can use 6-pin output sockets.

In another embodiment, the mechanical claw component is a probe, so that it can move freely and over a wide range to different electrodes of the chip to perform multi-shock electrical measurements on our sample chips.

In another embodiment, the mechanical claw assembly is a probe or an AFM probe with a sensor. In this way, various characteristics such as the surface thickness of the sample can be characterized.

In another embodiment, the mechanical claw assembly is a tungsten needle, so that our sample can be grasped like chopsticks.

In another embodiment, the mechanical jaw assembly is a mechanical jaw, so that you can observe various actions such as stretching, squeezing or twisting of the sample in the SEM. These are like human hands. Obviously, we all know that hands are better than simple hands. The hand is much more convenient and flexible, and more movements can be achieved.

Referring to FIGS. 1 to 2, it is a scanning electron microscope platform 20 with dual robots, including a sample cup 10 and two nano-manipulation robots located inside the sample cup 10. The nano manipulator includes X-direction macro-motion linear drive module 41, Y-direction macro-motion linear drive module 40 and Z-direction macro-motion drive module, X-direction micro-motion linear drive module, Y-direction micro-motion linear drive module, Z-direction micro-motion drive Module, drive circuit board 30 and socket. 51. The driving circuit board 30 is fixed at the corresponding groove at the bottom of the sample cup 10 by screws to serve as a positioning reference for the entire driving part. Install the Z-direction macro-motion drive module at the bottom to reduce the interference of the magnetic field on the detection electron beam. Install the Y-direction micro-motion linear drive module parallel to the Z-direction macro-motion drive module; connect the X-direction micro-motion linear drive module with the Y-direction micro-motion linear drive module; connect the Z-direction micro-motion drive module with the X-direction micro-motion linear The drive module is connected; here, the order of the micro movements in the XYZ directions can also be adjusted, which is not limited to this. Finally, the X-direction macro-motion linear drive module 41 and the Y-direction macro-motion linear drive module 40 are installed on the topmost Z-direction micro-motion drive module. The other manipulator is installed in the same way and installed in a symmetrical way. As shown in Figure 1, the vertical stacking position of each linear drive module is circled. Through this vertical serial connection method, the movement stroke of the entire manipulator can be ensured, and the manipulator position can be reasonably and effectively reduced. The space occupied.

In addition, the socket is set on the macro motion linear drive module at the top of the nano-manipulator. Correspondingly, a mechanical claw assembly 50 can be provided, and the mechanical claw assembly 50 is detachably connected to the nano-manipulator. The mechanical claw assembly 50 is plugged and installed on the output socket. When in use, the sample is glued to the platform 20, and the platform 20 with the sample is gently inserted into the sliding block 21 for auxiliary installation. Gently place the auxiliary slide 21 on the corresponding sliding groove of the sample cup 10, and carefully push the auxiliary slide 21 until it touches one end of the hinge assembly. Then the platform 20 with the sample is pushed from the auxiliary installation slider 21 to one end of the hinge group and clamped by the spring plunger 22. The hinge group can drive the platform 20 to move up and down to realize sample movement. Here, the installation of the scanning electron microscope platform 20 is an existing technology and will not be described in detail. After that, a mechanical claw assembly 50, such as a probe or a mechanical clamping claw, is installed on the nanomanipulator, and finally the housing cover 11 is screwed on to complete the installation of the platform 20.

The above-mentioned embodiments are only preferred embodiments for fully explaining the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims

A scanning electron microscope sample stage with dual manipulators, which is suitable for Phenom desktop electron microscopes, is characterized in that it comprises a sample cup in which two nano-manipulation manipulators are symmetrically arranged.
The scanning electron microscope sample stage with dual manipulators according to claim 1, wherein the single nanomanipulation manipulator includes a first linear drive assembly on the top, and the first linear drive assembly includes an X-direction macro Moving linear drive module and Y-direction macro moving linear drive module.
The scanning electron microscope sample stage with dual manipulators according to claim 2, wherein the X-direction macro-motion linear drive module is located on the upper side of the Y-direction macro-motion linear drive module or the Y-direction macro-motion linear drive module Located on the upper side of the X-direction macro motion linear drive module.
The scanning electron microscope sample stage with dual manipulators according to claim 2, further comprising a second linear drive assembly, the second linear drive assembly is located on the lower side of the first linear drive assembly; the second linear drive assembly The linear drive assembly includes a Z-direction macro-motion drive module, an X-direction micro-motion linear drive module, a Y-direction micro-motion linear drive module, and a Z-direction micro-motion drive module that are stacked in series in the vertical direction.
The scanning electron microscope sample stage with dual manipulators according to claim 4, wherein the X-direction macro-motion linear drive module, the Y-direction macro-motion linear drive module and the Z-direction macro-motion drive module all include Driven by the macro motion linear guide drive.
The scanning electron microscope sample stage with dual manipulators according to claim 4, wherein the X-direction micro-motion linear drive module, Y-direction micro-motion linear drive module, and Z-direction micro-motion drive module all include piezoelectric Ceramic driven micro-motion linear actuator.
The scanning electron microscope sample stage with dual robots according to claim 1, wherein the nanomanipulation robot is a multi-degree-of-freedom robot.
The scanning electron microscope sample stage with dual manipulators according to claim 1, further comprising a mechanical claw assembly for manipulating the sample, and the mechanical claw assembly is detachably connected to the nanomanipulation manipulator.
8. The scanning electron microscope sample stage with dual manipulators according to claim 8, wherein the nano-manipulator is provided with a multi-pin socket, and the mechanical claw assembly is provided with a multi-pin plug matching the socket.
8. The scanning electron microscope sample stage with dual manipulators according to claim 8, wherein the mechanical jaw assembly is a probe, a probe equipped with a sensor, or a mechanical jaw.