KR20220088029A - Apparatus for Maintaining local vacuum of specimen treating apparatus - Google Patents

Abstract

The present invention relates to a device for maintaining a local vacuum of a sample processing device, and more particularly, the efficiency of generating charged particles for observation or processing of a sample and forming an aperture in a path for irradiating the sample to transfer the charged particles to the sample and to form a local vacuum around the sample to prevent scattering of charged particles and annihilation of secondary electrons for image composition, and double local vacuum to form and strengthen the local vacuum. It is possible to increase the efficiency of the local vacuum through the holding configuration, and relates to a local vacuum holding device of a sample processing apparatus that appropriately adjusts gas suction and discharge pressure of an inert gas for efficient vacuum maintenance.

Description

TECHNICAL FIELD [0001] Apparatus for Maintaining local vacuum of specimen treating apparatus

The present invention relates to a device for locally maintaining a vacuum around a sample in a sample processing device for processing or observing a sample. More specifically, it relates to precision processing and observation in the vicinity of the location of the sample in processing the sample under atmospheric pressure in an apparatus for precisely processing the sample using charged particles or irradiating the sample to observe the sample.

A scanning electron microscope is a representative device for precisely observing a sample. The scanning electron microscope irradiates an electron beam to the sample and uses electrons reflected from the sample by the electron beam irradiated to the sample or electrons irradiated to the sample. Generated secondary electrons are collected to compose an image of the sample. In order to compose the image of the sample, it is important to collect as much as possible the charged particles generated by the electron beam irradiated to the sample, including secondary electrons, through the detector. It is common to prepare and observe within.

Recently, research on scanning electron microscopy, which places a sample in the air and observes it, is being conducted, and to precisely observe a specific part of the display for process optimization of the display, or to analyze a component of a foreign substance, it is used to analyze a large-area display under atmospheric pressure. It is also used for

However, even when the sample is observed under atmospheric pressure, in order to maintain a vacuum in the barrel where the electron beam is formed and the objective lens, etc. are formed, the electron-passing membrane is arranged with a thickness that allows electrons to pass through, and the lifespan of the electron-passing membrane is short, so frequent replacement is required. In addition, since the sample is under atmospheric pressure, the electron beam passing through the electron-passing film is scattered by the atmosphere while it goes to the sample, or secondary electrons reflected or emitted from the sample are annihilated, making precise processing and observation difficult.

Korean Patent Application Laid-Open No. 2014-0027687 discloses a device for protecting an electron-passing film to prevent shortening of the life of the electron-transmitting film and a scanning electron microscope having the same. Since the electron-passing film is provided, there is a problem that maintenance of the electron-passing film is required, and it is difficult to precisely observe and process because scattering by the atmosphere between the sample and the electron-passing film and the disappearance of secondary electrons cannot be prevented.

The present invention is to solve the above problems, and it is possible to increase the efficiency of transferring the charged particles to the sample by generating charged particles for observation or processing of the sample and forming an aperture in the path for irradiating the sample with the sample. By making it possible to form a local vacuum around it, it is possible to prevent the scattering of charged particles and annihilation of secondary electrons for image composition. An object of the present invention is to provide a local vacuum holding device for a sample processing device that can increase the efficiency of the sample processing device and appropriately adjust the gas suction and the discharge pressure of the inert gas to maintain the vacuum efficiently.

In order to achieve the above object, the local vacuum holding device of the sample processing device of the present invention is a sample processing device for processing or observing a sample under atmospheric pressure using charged particles, and for processing or observing the sample under atmospheric pressure. is provided, a column unit emitting charged particles to observe the sample provided on the sample holder, and the column unit is accommodated therein and the charged particles emitted from the column unit are irradiated to the sample on the path A column housing including a provided aperture, a local vacuum holding unit for sucking the gas of the sample area in order to locally block the predetermined area where the sample is placed in the outer part of the aperture from the outside, and the local vacuum oil It is characterized in that it includes a local vacuum strengthening part provided at the outer part of the branch to prevent external gas from flowing into a predetermined area where the sample is placed.

In addition, the local vacuum holding part is characterized in that it comprises a suction part which surrounds part or all of the outer circumference of the aperture in the column housing and a vacuum pump communicating with the suction part.

In addition, the suction part of the local vacuum holding unit is characterized in that it is formed in a shape inclined to the column housing with respect to the sample.

In addition, the local vacuum reinforcing unit is characterized in that it comprises a gas supply unit for supplying an inert gas through the discharge unit and the discharge unit surrounding a part or all of the outer periphery of the local vacuum holding unit.

In addition, the pressure of the inert gas discharged through the discharge unit is characterized in that greater than or equal to the pressure sucked from the local vacuum holding unit.

In addition, the discharge part is characterized in that the inert gas is formed in a inclined shape to the column housing to be discharged in a direction away from the sample.

In addition, the inert gas supplied through the discharge part is characterized in that helium.

In addition, the discharge unit is characterized in that the gas discharged to the outside of the local vacuum holding unit is formed to be discharged in a helical type.

In addition, the local vacuum holding unit includes a suction unit surrounding part or all of the outer circumference of the aperture in the column housing, and the local vacuum strengthening unit is formed to surround part or all of the outer circumference of the suction unit. Including, characterized in that it is provided such that the distance from the aperture to the suction unit is smaller than the distance from the suction unit to the discharge unit.

In addition, the height of the portion between the local vacuum holding part and the local vacuum strengthening part based on the sample mounting table is formed to be smaller than the height of the outer part of the local vacuum strengthening part.

In addition, the column housing between the local vacuum holding part and the local vacuum strengthening part further includes a partition wall formed toward the sample mounting table.

In addition, the partition wall is characterized in that it is made of a material having elasticity.

The present invention having the above configuration forms an aperture in the lower part of the column housing through which the charged particles pass to prevent loss or scattering when the charged particles are irradiated to the sample, and secondary electrons emitted from the sample to the inside of the column housing. It can be prevented from being lost when it arrives.

In addition, scattering of charged particles and loss of secondary electrons can be minimized by locally maintaining the region where the sample is prepared in a high vacuum state.

In addition, it is possible to efficiently maintain a local vacuum state through a double barrier film that sucks gas around the sample and blows inert gas in the outer part.

In addition, it is possible to efficiently maintain a local vacuum by optimizing the slope of the inlet for sucking the gas and the outlet for blowing the inert gas and varying the height of the inlet and the outlet.

In addition, the vacuum around the sample can be efficiently maintained by adjusting the pressure of the suction gas and the pressure of the discharged inert gas.

1 is a schematic diagram of a local vacuum holding device of a sample processing device according to an embodiment of the present invention;
2 is a view showing an example of a lower portion of a column housing including an inlet and an outlet of a local vacuum holding device of the sample processing apparatus of the present invention;
3 is a view showing the local vacuum holding state around the sample by the local vacuum holding device of the sample processing apparatus of the present invention;
Figure 4a, 4b is a view showing the flow of gas discharged from the local vacuum strengthening unit of the present invention,
5 is a view showing an example in which the partition wall of the local vacuum holding device of the sample processing apparatus of the present invention is installed.

Hereinafter, the local vacuum holding device of the sample processing device according to the present invention will be described in detail with reference to the drawings.

1 is a schematic diagram of a local vacuum holding device of a sample processing device according to an embodiment of the present invention, and FIG. 2 is an example of a lower portion of a column housing including an inlet and an outlet of the local vacuum holding device of the sample processing device of the present invention 3 is a view showing the state of maintaining a local vacuum around the sample by the local vacuum holding device of the sample processing apparatus of the present invention, and FIGS. 4A and 4B are the flow of gas discharged from the local vacuum strengthening unit of the present invention 5 is a view showing an example in which the partition wall of the local vacuum holding device of the sample processing apparatus of the present invention is installed.

The present invention processes a sample using charged particles having high energy or collects particles emitted from the sample such as secondary electrons or X-rays emitted by charged particles injected into the sample by irradiating the charged particles into the sample. It relates to a local vacuum holding device used in the imaging sample processing device. The charged particle may be an electron beam or a FIB (Focused Ion Beam), including any charged particle plane used for processing or observing a sample. A typical example of a device for imaging a sample is a scanning electron microscope. The scanning electron microscope collects secondary electrons from the sample to form an image of the sample. However, since secondary electrons have low energy and are easily annihilated in the atmosphere, it is common to observe/analyze samples in a high vacuum chamber. In addition, the processing apparatus of the sample using the FIB is usually processed in a chamber in which a vacuum atmosphere is formed for high-precision processing. However, when processing a sample in a chamber, there is a problem in that it is impossible to process a sample of a large area because the sample needs to be pre-processed in order to observe or process the sample in a vacuum and the sample is processed in the chamber. The sample processing apparatus of the present invention is an apparatus for processing a sample in a standby state in order to solve the problems of the conventional sample processing apparatus having a chamber structure. It is difficult to precisely observe and process, and to solve this problem, there is provided a device for maintaining a local vacuum around the sample.

In the sample processing device for processing or observing a sample prepared under atmospheric pressure using charged particles, the local vacuum holding device of the sample processing device of the present invention fixes the sample S to process or observe the sample S at atmospheric pressure. The column unit 200 and the column unit 200 for emitting charged particles having energy to process or observe the sample mounting table 100 and the sample S fixed to the sample mounting table 100 are housed therein. A column housing 300 in which an aperture 310 is provided on the path through which charged particles emitted from the column 200 are irradiated to the sample S and surrounds the path through which the charged particles are irradiated to the sample S at the lower portion. And a local vacuum holding part 400 for sucking the gas around the sample (S) in order to form a local vacuum by separating a certain area in which the sample (S) is fixed at the outer part of the aperture (310) from the outside and It is provided at the outer portion of the local vacuum holding unit 400 and comprises a local vacuum strengthening unit 500 for discharging gas to strengthen the vacuum state around the sample (S) formed by the local vacuum holding unit 400 . . In addition, it may further include a control unit 600 for controlling the local vacuum holding unit 400 and the local vacuum strengthening unit 500 to adjust the local vacuum state around the sample (S).

The sample mounting table 100 of the present invention is configured to fix the sample S to be observed or processed under atmospheric pressure. The sample mounting table 100 has a configuration in which the sample S is fixed, and it is preferable to set the size of the sample mounting table 100 according to the size of the sample S. In addition, since several places can be processed or observed in the sample S, it is preferable to be configured to be movable in the X-axis and Y-axis while the sample S is fixed. Since the separation distance can be adjusted, it can be configured to be movable in the Z-axis. Above all, as the processing or observation of the sample S must be performed with very high precision, it is preferable that the sample mounting table 100 is configured to reflect the vibration design so as not to be affected by the surrounding vibration. In addition, when processing or observing a large-area display, a device for transporting the display may be added to enable in-line processing, and negative pressure may be formed on the sample mounting table 100 for fixing the display. A configuration may be added, and if necessary, a lighting device may be provided under the sample mounting table 100 .

The column unit 200 of the present invention is configured to discharge charged particles for processing or observing the sample S provided on the sample mounting table 100 . Of course, any configuration that processes the sample (S) or emits particles that can be observed as described above is applicable. Since the sample processing apparatus of the present invention is a device capable of processing or observing the sample S, it is preferable to utilize an FIB that has high energy and can be processed rather than a configuration in which the column unit 200 emits an electron beam. FIB is largely divided into an ion source that emits charged particles and a part that aligns and focuses the ion beam emitted from the ion source. Extraction of the ion beam from the ion source consists of one end of the ion source as a tip and is extracted by applying a strong electric field. The extracted ion beam is aligned using a lens, a deflector, etc. and focused to a desired position. The ion beam emitted from the FIB has the advantage of being able to observe the sample or perform precise processing such as milling and drilling with a single source, so it can be used in devices that process complex samples. Since the column unit 200 should focus after generating and aligning the charged particles, it is preferable to place the charged particles in a high vacuum atmosphere in order to efficiently generate and precisely align and focus the charged particles.

The column housing 300 of the present invention is configured in the form of a chamber in which the column part 200 for generating charged particles is provided therein. In the column housing 300, it is necessary to align and focus the column unit 200 that generates charged particles and the charged particles generated in the column unit 200 to a desired position. A deflector and the like are provided inside, and a detector for collecting charged particles such as secondary electrons emitted from the sample when the sample is observed may be included therein. As described above, various components are provided inside the column housing 300, and a required degree of vacuum may be different depending on the role performed by each component. . The lower portion of the column housing 300 of the present invention has an aperture in order to precisely irradiate charged particles to process the sample S prepared under atmospheric pressure and efficiently collect particles such as secondary electrons emitted from the sample S. 310 is provided. Conventionally, since a sample is processed in a chamber in which a vacuum atmosphere is formed, there is no need for a separate aperture configuration or a structure that is shielded with a thin film. In the case of a structure shielded by a thin film, it is difficult to precisely investigate the charged particles and there are cases where the particles emitted from the sample do not pass through the thin film, so precise observation/analysis is difficult. In addition, since the thin film has to be replaced at regular intervals, maintenance is essential, so it is difficult to efficiently operate the sample processing device. By providing an aperture 310 in the column housing 300 of the present invention, precise sample processing is possible and efficient operation is possible. However, due to the aperture 310, it is difficult to maintain a high vacuum inside the column housing 300, and there is a problem that scattering occurs by gas molecules in the atmosphere. By forming and maintaining a local vacuum around the sample S through the part 500, precise processing and observation/analysis are possible.

The local vacuum holding unit 400 of the present invention is configured to form a degree of vacuum in the vicinity of the sample (B) by sucking the atmosphere around the sample (S). The local vacuum holding unit 400 is a vacuum pump for sucking the air through the suction unit 410 and the suction unit 410 for sucking the air in the vicinity of the sample (B) to form a vacuum degree of the vicinity of the sample (B). (420) is included. The suction unit 410 may be provided to face the sample S as shown in FIGS. 1 to 5 to more efficiently suck the air in the vicinity of the sample B to form a local vacuum. The atmosphere contains various gases, mostly nitrogen and oxygen. Since nitrogen and oxygen have relatively large molecular sizes, they are a major factor in scattering charged particles emitted from the column unit 200, and the local vacuum holding unit 400 sucks gas having such a large molecular size in the vicinity of the sample (B). It is a configuration that prevents particles such as scattering or secondary electrons emitted from the sample S from being annihilated.

The local vacuum strengthening unit 500 of the present invention is provided on the outside of the local vacuum holding unit 400 to strengthen and maintain the local vacuum formed in the vicinity of the sample (B) in the local vacuum holding unit 400 to supply an inert gas. It is a configuration for spraying and discharging. It is configured to include a discharge unit 510 provided to face the opposite side of the sample S to inject the inert gas and a gas supply unit 520 for supplying the inert gas to be discharged through the discharge unit 510 . The discharge unit 510 is preferably formed to face the opposite side of the sample as opposed to the suction unit 410 of the local vacuum holding unit 400, which minimizes the inflow of the discharged gas into the vicinity of the sample (B) and This is because it is possible to effectively prevent the inflow of open air into the vicinity of the sample in which the local vacuum is formed (B). The gas discharged from the local vacuum strengthening unit 500 is preferably an inert gas, because the inert gas is less likely to scatter or annihilate charged particles or secondary electrons emitted from the sample (S) because of its low reactivity. That is, even if the gas discharged from the local vacuum strengthening unit 500 flows into the vicinity of the sample (B), it is possible to suppress the possibility of scattering or annihilation by reducing the probability of causing a reaction with charged particles or secondary electrons. As the inert gas, it is preferable to discharge a gas having a low molecular weight, such as helium, rather than a gas having a high molecular weight.

The position of the suction unit 410 of the local vacuum holding unit 400 and the discharge unit 510 of the local vacuum strengthening unit 500 is the distance L1 between the aperture 310 and the suction unit 410 is suctioned. It is preferable to form it to be smaller than the separation distance L2 between the part 410 and the discharge part 510 . This is because it is possible to easily form a degree of vacuum in the vicinity of the sample (B) through the suction unit 410 and minimize the inflow of the gas discharged from the discharge unit 510 into the vicinity of the sample (B). In addition, the height W1 between the target mounting table 100 and the discharge unit 510 is preferably formed to be higher than the height W2 between the suction unit 410 . This is because the gas discharged from the discharge unit 510 is discharged more efficiently to the outside, so that the inflow into the vicinity of the sample (B) is minimized, and through this, the degree of vacuum formed in the vicinity of the sample (B) can be more efficiently maintained. In addition, if the gas discharged from the discharge unit 510 is discharged in a helical type as shown in FIGS. 4A and 4B , not only can the air flowing in from the outside be more efficiently blocked, but also a vacuum is formed inside because the gas is discharged while rotating. because it is easy to do.

The control unit 600 of the present invention adjusts the suction pressure and the exhaust gas pressure of the local vacuum holding unit 400 and the local vacuum strengthening unit 500 to more efficiently maintain the degree of vacuum formed in the vicinity of the sample (B). is a configuration that In more detail, when a vacuum degree of 10 ^-3 Torr is formed in the vicinity of the sample (B) by the local vacuum holding unit 400, the pressure of the gas discharged from the local vacuum strengthening unit 500 depends on the degree of vacuum formed therein. because it has to be different. That is, when the gas is discharged at a pressure lower than the vacuum level formed inside, the discharged gas is more likely to flow into the interior than to the outside, and accordingly, the internal vacuum level may not be maintained, and the pressure may be excessively greater than the internal vacuum level. This is because, when the gas is discharged, the internal vacuum level cannot be maintained at the desired level. The control unit 600 of the present invention is configured to properly control the local vacuum holding unit 400 and the local vacuum strengthening unit 500 to maintain the local vacuum degree formed in the vicinity of the sample (B) at a desired level.

The partition wall 700 of the present invention is configured to physically block the sample from the outside in order to maintain the vacuum degree in the vicinity of the sample (B) at a desired level. It is preferable to provide in between. In addition, it is preferable to make the partition wall 700 of an elastic material in order to prevent damage to the sample mounting table 100 and maximize the sealing degree.

Sample table: 100 Column section: 200
Column housing: 300 Local vacuum holding part: 400
Local vacuum strengthening unit: 500 Control unit: 600
bulkhead: 700

Claims (12)

In the sample processing apparatus for processing or observing a sample under atmospheric pressure using charged particles,
A sample holder on which a sample is provided for processing or observing the sample under atmospheric pressure;
a column unit for discharging charged particles to process or observe the sample provided on the sample mounting table;
a column housing including an aperture accommodated therein and provided on a path through which the charged particles emitted from the column are irradiated to the sample;
And a local vacuum holding unit for sucking the gas of the sample portion to locally block the predetermined area in which the sample is placed in the outer portion of the aperture;
The local vacuum holding device of the sample processing device, characterized in that it is provided at the outer portion of the local vacuum holding unit and includes a local vacuum strengthening unit for preventing external gas from flowing into a predetermined area in which the sample is placed.
In claim 1,
The local vacuum holding unit of the sample processing apparatus, characterized in that it comprises a suction unit which surrounds part or all of the outer circumference of the aperture in the column housing and a vacuum pump in communication with the suction unit.
In claim 2,
The local vacuum holding device of the sample processing apparatus, characterized in that the suction part of the local vacuum holding unit is formed in a shape inclined to the column housing with respect to the sample.
In claim 1,
The local vacuum strengthening unit maintains a local vacuum of the sample processing device, characterized in that it comprises a gas supply unit for supplying an inert gas through the discharge unit and the discharge unit surrounding part or all of the outer circumference of the local vacuum holding unit. Device.
In claim 4,
The pressure of the inert gas discharged through the discharge unit is greater than or equal to the pressure sucked from the local vacuum holding unit.
In claim 4,
The discharge unit is a local vacuum holding device of the sample processing apparatus, characterized in that the inert gas is formed in a inclined shape in the column housing to discharge in a direction away from the sample.
In claim 4,
The inert gas supplied through the discharge unit is a local vacuum holding device of the sample processing device, characterized in that helium.
In claim 4,
The discharge unit is a local vacuum holding device of the sample processing apparatus, characterized in that the gas discharged to the outside of the local vacuum holding unit is formed to be discharged in a helical type.
In claim 1,
The local vacuum holding part includes a suction part surrounding part or all of the outer perimeter of the aperture in the column housing, and the local vacuum strengthening part includes a discharge part formed to surround part or all of the outer perimeter of the suction part, and ,
and a distance from the aperture to the suction part is smaller than the distance from the suction part to the discharge part.
In claim 1,
The local vacuum holding device of the sample processing apparatus, characterized in that the height of the portion between the local vacuum strengthening part and the local vacuum strengthening part based on the sample mounting table is formed to be smaller than the height of the outer part of the local vacuum strengthening part.
In claim 1,
The local vacuum holding device of the sample processing apparatus further comprising a partition wall formed toward the sample mounting table in the column housing between the local vacuum holding unit and the local vacuum strengthening unit.
In claim 11,
The partition wall is a local vacuum holding device of the sample processing device, characterized in that made of an elastic material.

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