JP2008262886A - Scanning electron microscope device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning electron microscope device in which an electron gun is maintained in vacuum. <P>SOLUTION: The scanning electron microscope 1 is provided with an electron gun 2 in which a metal film, a carbon film, a diamond film, and a diamond-like carbon film which transmit accelerating electrons and can endure the atmosphere are provided at the electron gun window 35, and a sealed container 33 is maintained in vacuum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a scanning electron microscope apparatus, and more particularly, to a scanning electron microscope apparatus that enables a pressure of a sample portion and a vacuum degree of a scanning electron microscope apparatus to be different.

2. Description of the Related Art A scanning electron microscope (SEM) that can observe a fine surface that cannot be seen with an optical microscope is widely used.

SEM is a method of scanning the surface of a substance with an electron beam and observing the shape and configuration of the substance surface with reflected electrons or secondary electrons from the surface.

The following documents are available for detectors used in SEM and SEM.

Scanning electron microscope http: // www. remus. dti. ne. jp / ￣KKKKwing / Basics of Electronics Engineering Chapter 6 Special Electron Tube Supervised by Yujiro Koike Modern Science

Since the life of the electron gun is short unless it is a high vacuum, when observing with an SEM, the sample is placed in a sample chamber evacuated to an ultra-high vacuum and observed.

However, in recent years, several new SEMs have been used for observation of living bodies.

That is, a method of wrapping a sample with a film that transmits an electron beam and does not pass a liquid (for example, Patent Document 1), or a method of separating a sample chamber and a scanning electron microscope apparatus main body by differential evacuation (for example, Patent Document 2). In addition, a method (for example, Patent Document 3) that separates the sample chamber and the electron microscope apparatus main body by using a film that can pass electrons and can withstand atmospheric pressure is disclosed.

JP 2005-529341 A JP 2006-190578 A JP 2006-147430 A

However, the conventional methods have the following problems.

First, in the method of wrapping a sample in a special capsule, it takes a double labor to put the sample in the capsule every time the sample is exchanged, and to return the sample chamber to the atmosphere, exchange the sample, and perform evacuation.

In addition, in the method of performing differential pumping, there is a problem that the atmosphere enters the electron gun somewhat, the degree of vacuum drops, the life of the electron gun is shortened, and high voltage is difficult to be applied. Once an ultra-high vacuum device such as an electron microscope is turned into a low vacuum, it takes a long time to return to the original ultra-high vacuum, and the performance deteriorates gradually.

Recently, electron beam emitters using carbon nanotubes or tungsten nanotubes have been used as electron beam emitters in electron microscopes from the filament system. This has a longer life than conventional high-temperature filament emitters, and since the temperature is low, there is no deviation in the accuracy of the electrodes due to temperature fluctuations, and high accuracy can always be maintained. However, to use these low-temperature electron beam emitters, it is an absolute requirement to maintain an ultrahigh vacuum.

Further, in the method of differential evacuation using the collodion film, the collodion film is not He leak tight, and the electron microscope barrel cannot be kept in a vacuum, and evacuation is always necessary.
In addition, the width of the orifice for differential evacuation is narrow and electron beam scanning is not possible, and it is necessary to move the sample stage itself instead of electron beam scanning. Problems with lifespan. Furthermore, it becomes difficult to maintain high voltage with high accuracy due to vibration.

The present invention has been made to solve such problems, and an object thereof is to provide a scanning electron microscope apparatus in which an electron gun is not exposed to the atmosphere and does not require differential pumping.

The present invention has been made to overcome such problems. That is, an electron emitter in an electron accelerating lens barrel that maintains a high vacuum accelerates the generated electrons, passes the converging lens and deflection lens through the electron beam transmission film, and is in the atmosphere or in a low vacuum. Alternatively, an electron microscope with an electron beam transmission film that emits electrons in an atmospheric gas is provided.

The electron beam transmissive film used in the present invention is a thin film that can withstand the differential pressure between the vacuum pressure inside the lens barrel and the external pressure, and can be vacuum sealed, and the electron beam transmissive window is sealed with a thin film. The problem was solved by paying attention to the fact that the tube can always maintain a high vacuum even when the sample is changed.

That is, the invention described in claim 1 has the following configuration. A vacuum container and an electron gun for keeping the inside vacuum; an electron beam irradiation means for guiding an electron beam emitted from the electron gun toward the sample; a scanning means for scanning the electron beam; and In a scanning electron microscope apparatus having an electron detection means for detecting electrons emitted from a sample by irradiation, the aperture is formed in an aperture window formed in an objective lens aperture or a vacuum partition provided in the vicinity of the objective lens aperture. The electron beam irradiation window is sealed with the diaphragm window or the electron beam transmission window with a thin film that transmits the electron beam and withstands the differential pressure between the vacuum pressure inside the vacuum vessel and the pressure outside the vacuum vessel, The scanning electron microscope apparatus has a configuration in which the area of the sealed diaphragm window or the sealed electron beam transmission window is wide enough to allow scanning of the electron beam with respect to the sample. .

This is preferable because even if the sample chamber is in an atmospheric pressure or reduced pressure state, the electron can scan the sample and obtain an image in a certain range while keeping the electron gun in an ultrahigh vacuum.

Further, the invention described in claim 2 has the following configuration.
That is, a vacuum container that keeps the inside in a vacuum, an electron gun, an electron beam irradiation unit that guides an electron beam emitted from the electron gun toward a sample, a scanning unit that scans the electron beam, and the scanned In a scanning electron microscope apparatus having an electron detection means for detecting electrons emitted from a sample by irradiation of an electron beam, a vacuum partition provided near an anode for accelerating the electron beam emitted from the electron gun A perforated electron beam transmission window, or an electron beam transmission window perforated in the anode attached to the vacuum partition,
A. Withstands the differential pressure between the vacuum pressure on the electron gun side of the vacuum barrier and the pressure on the opposite side of the electron gun,
B. It was set as the scanning electron microscope apparatus which took the structure sealed with the thin film which has the characteristic which permeate | transmits an electron.
In this way, the electron gun is always kept in a vacuum, and the life of the electron gun is extended.

Further, the invention described in claim 3 has the following configuration.

That is, a vacuum container and an electron gun for keeping the inside vacuum, an electron beam irradiation means for guiding an electron beam emitted from the electron gun toward a sample, a scanning means for scanning the electron beam, and the scanned electron A sealed container characterized by the following four points in a scanning electron microscope apparatus comprising: an electron detecting means for detecting electrons emitted from a sample by irradiation of a line; 1. Built-in electron gun An electron beam transmission window provided in the vacuum partition of the sealed container,
2. Sealed with a thin film that can withstand the differential pressure between the vacuum pressure inside the sealed container and the pressure outside the sealed container, and that can be vacuum-sealed and has the property of transmitting electrons. It can be removed from the scanning electron microscope device,
4). It was set as the scanning electron microscope apparatus which took the structure equipped with a vacuum seal material and being attachable to a scanning electron microscope apparatus.

This is preferable because the life of the electron gun is prolonged, and the electron gun can be replaced with the sealed container when the life is reached.

Moreover, in the invention of Claim 4, it was set as the following structures. That is, the scanning electron microscope apparatus according to claim 1, 2 or 3, wherein the scanning means for scanning the electron beam is installed outside the vacuum vessel. It was.
This is preferable because even if the width of the electron beam transmission window is narrow, scanning of the electron beam can be executed to obtain a wide range of sample images.

A removable cylinder is hermetically connected to the downstream of the electron beam of the electron beam column, and an electron beam transmission film of a size capable of electronic scanning is bonded to the tip of the cylinder, and an electron scanning coil is provided outside the cylinder. By arranging, electron beam scanning is performed from the atmosphere or atmosphere. This can reduce the number of parts inside the vacuum and easily maintain a high vacuum.
Further, the invention described in claim 5 has the following configuration.

That is, in the scanning electron microscope apparatus according to claim 1, claim 2, claim 3, or claim 4, a configuration is provided in which a cover that surrounds the electron beam that exits the electron beam transmission window and faces the sample is installed. A scanning electron microscope apparatus was obtained.

This is preferable because secondary electrons generated when the electron beam runs through the atmosphere and collides with the atmosphere do not leak to the outside.
It is also preferable because the detector can be installed near the sample by increasing the distance between the sample and the electron beam transmission window. Moreover, it is preferable because the scanning means can be installed on the atmosphere side.

Further, the invention described in claim 6 has the following configuration. That is, in the scanning electron microscope apparatus according to claim 1, claim 2, claim 3, claim 4, or claim 5, the thin film that seals the electron beam transmission window is made of metal or glassy carbon. Or a vacuum tight composition comprising at least one of tiremond, diamond-like carbon, dielectric, doped diamond, doped diamond-like carbon, or doped dielectric. The scanning electron microscope apparatus has a configuration that is preferably a helium leak tight thin film.

This is preferable because the electron gun can be kept in an ultrahigh vacuum even if the sample chamber is brought to atmospheric pressure or reduced pressure.

Further, the invention described in claim 7 has the following configuration.

That is, in the scanning electron microscope apparatus according to claim 1, claim 2, claim 3, claim 4, claim 5, or claim 6, a titanium getter pump inside the vacuum container or the sealed container, or In addition, a storage type pump such as a titanium sublimation pump or an ion pump, or a non-evaporable getter material is disposed, and the inside of the vacuum vessel or the sealed vessel is always kept in an ultrahigh vacuum. It was set as the scanning electron microscope apparatus which takes the structure which is an electron microscope apparatus.

This is preferable because it does not require a turbo pump for exhausting the outside of the vacuum vessel and can maintain a high degree of vacuum.

Further, the invention according to claim 8 has the following configuration.
That is, in the scanning electron microscope apparatus according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, or claim 7,
A bias power source for applying a bias between the disk-shaped cathode electrode and the sample or the sample stage is provided on the disk-shaped cathode electrode in which the electron detecting means is installed outside the vacuum chamber (electron beam column). Secondary electrons are guided to the disk-shaped cathode electrode, and the disk-shaped cathode electrode is divided into several parts, and the divided disk-shaped cathode electrodes are connected to an insulation amplifier to detect secondary electrons. A scanning electron microscope apparatus having a configuration was adopted.

In this way, secondary electrons accelerated toward the disk-like cathode electrode at atmospheric pressure or reduced pressure multiply by collision with gas molecules, grow to a detectable current, and reach the disk-like cathode electrode. For this reason, it is preferable because an expensive secondary electron multiplier tube which is easily broken is unnecessary.

A quenching gas introduction hole for secondary electron amplification is provided in the sample container, and the gas flow rate is adjusted so as to maintain a constant gas pressure.

According to the present invention, since the electron gun, the acceleration tube, and the electron converging part are always kept in a high vacuum, an electron beam emitter optimal for an electron microscope can be used, and there is no contamination of the lens barrel due to vacuum deterioration during sample insertion. , Always maintaining the best performance and less maintenance. In addition, since an image can be obtained by scanning the sample with an electron beam at any pressure from atmospheric pressure to ultrahigh vacuum, it can be used for biological samples and environmental inspections.

Presentation of the principle in the patent of the present application First, calculation and experimental results for realizing the optimum embodiment will be shown for the following four items.
1. 1. Distance that can travel through air or film at a constant pressure with almost no scattering of electrons. 2. The thickness of the film that can transmit electrons and withstand a certain pressure. 3. Voltage for guiding electrons emitted from the sample to the detector and the width of the detector A method of attaching a thin film that transmits electron beams, withstands atmospheric pressure, and does not allow gas transmission to a hard frame such as an electron transmission window

The embodiment will be described on the basis of the calculation and the experimental result, but the experiment and the calculation result will not be mentioned in the embodiment.

(Distance that can travel through the atmosphere and film at a constant pressure with almost no electrons scattered)

Table 1 shows the unscattered electron reach from 11 KeV to 200 KeV and the distance that the carbon film loses 5% of the incident energy.

Here, the unscattered reach distance refers to a distance at which 95% or more of electrons are not scattered more than 5 nm from the center of the incident axis even if the electrons collide with molecules in the film.

However, this value of 5 nm is one digit larger than the actual value and is a value that allows for sufficient safety.

The value of 5 nm indicates the amount of displacement from the point where each electron is incident.

Table 1 Values without units are in microns.

In this way, in the case of a carbon film or an aluminum film, the thickness of the film that allows the electron beam to pass through without being scattered and can be vacuum-sealed becomes 5 μm or 2.5 μm.

The area that can withstand atmospheric pressure with this thickness is as follows.
7 * 10 ^ 10N / m ^ 2 = Pa

(Applied voltage that causes the detector to collect secondary electrons to obtain SEM images)

Since the average free path of low-speed electrons in the atmosphere is 0.5 μm, in order for the electrons to accelerate 1.5 eV at the distance of the average free path, when the distance between the sample and the detector is 7 mm, 20 KV An applied voltage is required.

With this electric field strength, even if electron gas amplification occurs due to electron collision, it does not lead to atmospheric pressure discharge.

In order to prevent discharge even when the electric field strength is increased, it is necessary to fill an insulating gas such as SF6 or carbon tetrachloride between the sample and the detector.

When accelerating by 4.5 eV in the mean free path, the distance between the sample and the detector can be reduced to 2.3 mm.

With this voltage application of 20 KV, if the film thickness of the carbon film is 0.5 μm, most electrons pass through the film.

Because the energy of electrons accumulates potential energy except when gas is excited or ionized by scattering in the middle, some electrons pass through the film provided in the detector with energy of about 20 KeV, Get inside. [0065]
This method can be applied to a detector for detecting a signal by exciting a fluorescent substance to emit light and amplifying the light with a photomultiplier tube.

In this way, the fluorescent material can be placed on the vacuum side of the carbon film, but the fluorescent material can be applied to the light-transmitting film and the fluorescent material can be placed on the atmosphere side.

In this case, the applied voltage can be further lowered.

Not only diamond and quartz films but also glassy carbon films of 0.5 μm can transmit some light.

In addition, a dielectric film of 0.5 μm can be used because it does not only transmit light somewhat, but in recent years transparent ones are on the market.
To prevent the electrons incident on the sample from being affected by this electric field, the potential of the detector may be determined based on the potential of the sample so that the electric field of the sample is not affected.

However, even if this is not the case, if the electric field is applied to the axis object around the central axis of the electron beam incident on the sample, even if the electrons incident on the sample are somewhat accelerated or decelerated, no problem is caused.
Alternatively, the accelerated secondary electrons may be directly incident on the photomultiplier tube through a film of about 0.5 μm without changing the electrons into light by the fluorescent material.

(Method of attaching a thin film to a hard frame such as an electron transmission window)
What is necessary is just to metal-bond a film | membrane and a frame using a brazing material. Diffusion bonding is also possible.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows a first embodiment according to the present invention, wherein 1 is a scanning electron microscope apparatus, and 2 is an electron gun.

FIG. 1A is an explanatory view of the electron gun, in which 30 is a field emitter tip, 32 is a first anode, 33 is a sealed container, 34 is a second anode, and 35 is an electron gun window. The electron gun window 35 is vacuum sealed with an electron beam transmission film 36.

The second anode 34 and the sealed container 33 may be bonded to vacuum tight via an insulator, or the sealed container may be made of an insulator.

The first anode 32 and the field emitter tip 30 are also insulated from the sealed container 33.
The circuit diagram of the electron gun is shown in FIG. 3 for the field emission type and in FIG. 3A for the thermionic emission type.

Since both are well known, the description is omitted.

Returning to FIG. 1 again, a description will be given of attaching the electron gun 2 of FIG. 1A to the scanning electron microscope apparatus 1.

The sealed container 33 of the electron gun 2 is attached to the vacuum container 3 with bolts while being vacuum-sealed using the seal 31.

In FIG. 1, 5 is a first focusing lens, 6 is a second focusing lens, 7 is a scanning coil, 8 is an objective lens, 9 is an objective lens aperture, and 10 is an aperture window formed in the objective lens aperture 9.

The aperture window 10 can be vacuum-sealed with the electron beam transmission film 136.

When the aperture window 10 is sealed with the electron beam transmission film 136, the electron gun window 35 is not required to be vacuum sealed, but it is safe to further seal with the electron beam transmission film 36 to protect the field emitter chip 30. Will increase.

When the diaphragm window 10 is vacuum-sealed with the electron beam permeable membrane 136, after exhausting from the exhaust port 15, the valve 28 can be closed and the pumps can be removed.

On the other hand, when the diaphragm window 10 is not vacuum-sealed by the electron beam permeable film 136, it is necessary to connect the high vacuum pump 20 exhausted by the back pump 21 to the exhaust port 15 and perform differential exhaust.

When the non-evaporable getter 37 is built in the vacuum vessel 3, gas is emitted from the non-evaporable getter 37 during exhausting by the high vacuum pump 20. After gas has come out from the non-evaporable getter 37, it is necessary to close the valve 28. In this way, the non-evaporable getter 37 occludes the impure gas, and the inside of the vacuum vessel 3 is kept in an ultrahigh vacuum.

It should be noted that the non-evaporable getter is also preferably sealed in the electron gun shown in FIG. 1-a, FIG. 2 or FIG. Non-evaporable getter materials include iron, aluminum, zirconium, barium and cobalt. Non-evaporable getters are well known and will not be described further.

When observing the sample 12 under atmospheric pressure, the sample chamber 22 is not necessarily required, but a 1 KV is applied to attract secondary electrons, reflected electrons, and Auger electrons 13 accompanying the incident electron 11 to the detector 14. In order to prevent discharge from being caused by a voltage of 50 KV to 50 KV, it is preferable to have the sample chamber 22 in order to fill the sample chamber 22 by introducing a gas that is difficult to discharge such as He or SF6.

Reference numeral 17 denotes a gas introduction pipe through which such an inert gas flows from the gas cylinder 19 into the sample chamber 22 via the mass flow controller 18.

  Of course, an oil rotary pump, an oil-free thread groove pump, or a high vacuum pump can be used for the sample chamber 22 to reduce the pressure to a required level.

  In FIG. 1, 24 is a sample chamber exhaust port, 25 is a high vacuum pump, and 26 is a back pump, and shows an exhaust system for lowering the pressure in the sample chamber 22.

Thus, when the sample is observed with the pressure in the sample chamber 22 lowered, the film thickness of the electron beam transmitting film 36 that seals the diaphragm window 10 can be reduced.

However, when the sample chamber 22 is set to the atmosphere in order to replace the sample 12, it is necessary to protect the diaphragm window 10 by closing a valve (not shown) so that the thin film is not broken at atmospheric pressure.

Further, instead of the valve, a conducting tube (not shown) of the sample chamber 22 and the vacuum vessel 3 may be opened to return to the atmospheric pressure so as not to generate a differential pressure.

The electron beam permeable film is not limited to the electron gun window 35 and the diaphragm window 10 described above, but a vacuum at an intermediate position between the first focusing lens 5 and the second focusing lens 6 or between the second focusing lens 6 and the scanning coil 7. A partition wall may be provided, an electron beam transmission window may be formed in the vacuum partition wall, and the electron beam transmission window may be vacuum sealed with an electron beam transmission film. An example of this seal is shown in FIG.

A vacuum partition wall 301 and an electron gun transmission window 302 bored in the vacuum partition wall may be provided at positions a to h in FIG.

In this case, it is sufficient for the electron gun 2 side to adsorb the impure gas with a getter material or the like, but it is preferable that the sample chamber 22 side is differentially evacuated with a low vacuum pump or a high vacuum pump.

  However, if the scanning electron microscope apparatus 1 is made compact, the scattering of the electron beam is reduced, so that differential pumping may not be necessary.

  The scanning coil 7 and the focusing lenses 5, 6 and 8 can be of various types such as a magnetic field type and an electrostatic type. There are various methods such as an Einzel lens and a mesh lens in the electrostatic type, and there are a quadrupole type and a hexapole type in the magnetic field type. These are merely examples, and embodiments of the present patent are not limited to these. The number of convergent lenses can be increased or decreased as necessary.

FIG. 2 is a view showing a second embodiment, and a window support 43 having an electron gun window 35 is provided separately from the second anode 34.

FIG. 9 shows a third embodiment in which a second scanning coil 23 is added in addition to the scanning coil 7. The electrons bent by the second scanning coil 23 are bent by the scanning coil 7 in the direction opposite to the initial direction so as to pass through the aperture window 10.

In this way, even if the area of the aperture window 10 is small, the center of the optical axis of the electron beam 500 can pass through the center of the aperture window 10 and the sample 12 can be scanned.

If the center of the optical axis of the electron beam passes through the center of the diaphragm window 10, an SEM image with good magnification, resolution, and brightness can be obtained even if the area of the diaphragm window 10 is small.

In this embodiment, two scanning coils are installed at different locations, but two scanning coils may be adjacent to each other as shown in FIG.

FIG. 5 shows where the narrow aperture window 10 should be placed.
This figure shows a driving circuit for scanning an electron beam in the X direction and an electron beam driven in the X direction, and the Y direction is omitted.

Reference numeral 81 denotes an optical axis of an incident electron beam. The electron beam bent by the electron gun side deflection coil 82a is bent in the opposite direction by the next sample side deflection coil 82b, and is narrowed by the objective lens 8, and the electron beam convergence position 92 is obtained. Comes to the center of the optical axis.

When the aperture window 10 provided on the objective lens aperture 9 is aligned with the electron beam convergence position 92, the area of the aperture window 10 can be minimized.

However, since the electron beam convergence position 92 changes depending on the acceleration voltage of the electron beam and the difference in the scanning range of the electrons,
A. An average position of the electron beam convergence position 92; Electron beam convergence position 92 in a state of high magnification at which accuracy is most required
It is good to place the aperture window 10 in the center.

In addition, a drive mechanism that changes the position of the aperture window 10 according to changes in the electron beam convergence position 92 depending on conditions may be provided, and the position of the aperture window 10 may be changed according to the displacement of the position of the electron beam convergence position 92. good.

FIG. 6 shows a fourth embodiment in which the atmospheric scanning coil 29 is built in the sample chamber 22.

In this case as well, even if the area of the aperture window 10 is small, the center of the optical axis constantly passes through the center of the aperture window 10, and the resolution, magnification, and brightness are not reduced even when the electron beam is scanned.

FIG. 7 shows an incident electron cover 16 for absorbing secondary electrons emitted from the collision of incident electrons 11 with molecules in the atmosphere in the fifth embodiment.

In this way, it is possible to prevent the adverse effects of secondary electrons that come out of collision with the atmosphere.
FIG. 8 shows a sixth embodiment in which a second anode 34 serving as an accelerating electrode of the electron gun 2 is attached to a vacuum partition wall 38 in a leak tight manner, and an electron gun window 35 is formed in the second anode. .
An electron beam transmission film 36 is metal-bonded to the electron gun window with leak tight.

FIG. 10 shows a seventh embodiment in which the electron microscope 3 having an electron scanning magnet is separated from the material chamber 22 by a vacuum tight electron beam transmission window at the electron downstream end. Thus, the secondary electrons are amplified by applying a bias voltage 78 to electrons generated from the sample due to the interaction of the electron beam irradiated on the sample. Electrons from the sample are amplified by an insulation amplifier, synchronized with a deflection coil, and observed by a CRT monitor 95.

Secondary electrons are amplified by introducing a quenching gas from the cylinder 19 through the valve 28 into the sample chamber 22.

As a quenching gas for electron amplification, helium gas, argon gas, CH4 or SF6 gas is preferably enclosed or circulated.

The scanning electron microscope apparatus disclosed here has a long electron gun life, and the sample can be observed by scanning the electron beam regardless of the pressure from any pressure of atmospheric pressure to ultrahigh vacuum. Can be omitted if necessary, and it can be used in a wide range of fields, not limited to semiconductors and biological samples, such as ease of use of equipment, reduction of equipment price, reduction of running cost, reduction of installation area, and portability. It is expected to be able to enter not only scanning electron microscope devices but also some optical microscope markets.

It is the schematic of the scanning electron microscope apparatus which concerns on Example 1 of this invention. The example which attached the electron beam permeation | transmission window at the exit of the electron gun chamber in the Example of this invention. It is the schematic of the electron gun which concerns on Example 2 of this invention. An electron transmission window is attached to the second anode according to the second embodiment of the present invention. It is a circuit diagram of an electron gun. It is a circuit diagram of an electron gun when a Wehnelt electrode is equipped. It is the schematic explaining the position vacuum-sealed with an electron beam permeable film. It is the schematic of the scanning electron microscope apparatus which concerns on Example 3 of this invention. It is the schematic of the scanning electron microscope apparatus which concerns on Example 4 of this invention. It is the schematic of the scanning electron microscope apparatus which concerns on Example 5 of this invention. It is the schematic of the scanning electron microscope apparatus which concerns on Example 6 of this invention. It is the schematic of the scanning electron microscope apparatus which concerns on Example 3 of this invention. It is the schematic of the scanning electron microscope apparatus which concerns on Example 7 of this invention.

Explanation of symbols

a, b, c, d, e, f, g, h: a place where an electron gun transmission window vacuum-sealed by a vacuum partition and an electron beam transmission film can be installed 1 scanning electron microscope device 2 electron gun 3 vacuum vessel 5 First focusing lens 6 Second focusing lens 7 Scanning coil 8 Objective lens 90
9 Objective lens aperture 91
10 aperture windows 85
11 incident electrons 12 samples 89
13 Secondary electrons, backscattered electrons, Auger electrons 14 detector 15 exhaust port 16 incident electron cover 17 gas introduction pipe 18 mass flow controller 19 gas cylinder 20 high vacuum pump 21 back pump 22 sample chamber 23 second scanning coil 24 sample chamber exhaust port 25 High vacuum pump 26 Back pump 27 Sample take-out port 28 Valve 29 Atmospheric scanning coil 30 Field emitter tip 31 Seal 32 First anode 33 Sealed container 34 Second anode 35 Electron gun window 36 Electron transmission film 37 Non-evaporable getter material 38 Vacuum barrier 39 objective lens aperture vacuum barrier 43 window support 60 field emission electron gun 64 virtual light source 65 flushing circuit 66 extraction voltage circuit 67 emission 68 acceleration voltage circuit 71 cathode filament 72 Wehnelt 73 crossover point 74 anode 75 fi Ment circuit 76 filament current 77 acceleration voltage 78 bias circuit 79 emission meter 81 electron beam optical axis center 82a electron gun side deflection coil 82b sample side deflection coil 83 low magnification electron beam path 84 high magnification electron beam path 85 magnification setting boost circuit 86X Directional electron gun side scanning signal generation circuit 87X Direction sample chamber side scanning signal generation circuit 88 Cathode ray tube (CRT)
92 Electron beam convergence position 93 Pickup electrode 94 Insulation amplifier 95 Braun tube CRT monoter 100 Sample stage 101 Electron current 128 Valve 136 Electron beam transmission film 600 Electron beam 301 Vacuum partition wall 302 Electron beam transmission window 500 Field emission electron

Claims (8)

A vacuum vessel and an electron gun for keeping the inside vacuum, an electron beam irradiation means for guiding an electron beam emitted from the electron gun toward the sample,
A diaphragm window formed in the objective lens diaphragm in a scanning electron microscope apparatus having scanning means for scanning the electron beam and electron detection means for detecting electrons emitted from the sample by irradiation of the scanned electron beam Or, an electron beam irradiation window formed in a vacuum partition provided in the vicinity of the objective lens stop transmits electrons, and is a thin film that can withstand the differential pressure between the vacuum pressure inside the vacuum vessel and the pressure outside the vacuum vessel. Sealed by the diaphragm window or the electron beam transmission window, and the area of the sealed diaphragm window or the sealed electron beam transmission window is wide enough to allow the electron beam to scan the sample. A scanning electron microscope apparatus characterized by comprising: A vacuum container and an electron gun for keeping the inside vacuum; an electron beam irradiation means for guiding an electron beam emitted from the electron gun toward the sample; a scanning means for scanning the electron beam; and An electron beam perforated in a vacuum partition provided near an anode for accelerating the electron beam emitted from the electron gun in a scanning electron microscope apparatus having an electron detection means for detecting electrons emitted from the sample by irradiation A transmission window or an electron beam transmission window drilled in the anode attached to the vacuum bulkhead,
A. Withstands the differential pressure between the vacuum pressure on the electron gun side of the vacuum barrier and the pressure on the opposite side of the electron gun,
B. A scanning electron microscope apparatus characterized by being sealed with a thin film having a property of transmitting electrons. A vacuum container and an electron gun for keeping the inside vacuum; an electron beam irradiation means for guiding an electron beam emitted from the electron gun toward the sample; a scanning means for scanning the electron beam; and An electron detection means for detecting electrons emitted from the sample by irradiation, and a sealed container characterized by the following four points in a scanning electron microscope apparatus. 1. Built-in electron gun An electron beam transmission window provided in the vacuum partition of the sealed container,
2. Sealed with a thin film that can withstand the differential pressure between the vacuum pressure inside the sealed container and the pressure outside the sealed container, and that can be vacuum-sealed and has the property of transmitting electrons. It can be removed from the scanning electron microscope device,
4). What is claimed is: 1. A scanning electron microscope apparatus comprising a scanning electron microscope apparatus that can be attached using a vacuum seal material. In the scanning electron microscope apparatus of Claim 1 or Claim 2 or Claim 3,
A scanning electron microscope apparatus, wherein scanning means for scanning the electron beam is installed outside the vacuum vessel.
A scanning electron microscope apparatus comprising an electron beam transmission window disposed at a tip of a removable cylinder in the scanning electron microscope apparatus, and a deflection coil disposed on the atmosphere side of the cylindrical portion. 5. The scanning electron microscope apparatus according to claim 1, wherein the electron beam transmitting window exits the electron beam transmission window and surrounds the electron beam toward the sample. Scanning electron microscope apparatus. 6. The scanning electron microscope apparatus according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the thin film sealing the electron beam transmitting window is a metal, glassy carbon, or , Tire tight, or diamond-like carbon, or dielectric, or doped diamond, or doped diamond-like carbon, or doped dielectric. A scanning electron microscope apparatus characterized by being a leak-tight thin film. The scanning electron microscope apparatus according to claim 1, claim 2, claim 3, claim 4, claim 5, or claim 6,
In the vacuum container or the sealed container, a storage pump such as a titanium getter pump, a titanium sublimation pump, or an ion pump, or a non-evaporable getter material is disposed, and the vacuum container or the sealed container is inside. Is maintained at an ultrahigh vacuum at all times. The scanning electron microscope apparatus according to claim 1 or claim 2, or claim 3, or claim 4 or claim 5, or claim 6 or claim 7, wherein the electron detecting means is installed outside the vacuum chamber. A bias power source for applying a bias between the disk-shaped cathode electrode and the sample or the sample stage is provided, and secondary electrons from the sample are guided to the disk-shaped cathode electrode, and the number of the disk-shaped cathode electrodes is A scanning electron microscope apparatus characterized in that the disk-shaped cathode electrode in the divided peripheral portion is connected to an insulation amplifier to detect secondary electrons.

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