JP2001093456A - Charged particle beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the vibration of a lens-barrel. SOLUTION: In a body of a microscope which is placed on a fixed position on a floor 3, attachment plates 12A and 12B for legs 10A and 10B of a reinforcement material 10 are fixed at an upper end and a lower end of a rear part of one side of a stage 4 using screws so as to fix the reinforcement material 10 to the stage 4, on the other hand, attachment, plates for legs 11A and 11B of a reinforcement material 11 are fixed at an upper end and a lower end of a rear part of an opposite side of the stage 4 using screws so as to fix the reinforcement material 11 to the stage 4. Attachment plates 16 and 15 for a boom member 13 are respectively fixed to a rear side of an attachment ring 17 at an upper portion of a lens-barrel and to the reinforcement material 10 using screws, on the other hand, attachment plates 19 and 18 for a boom member 14 are respectively fixed to the rear side of the attachment ring 17 at the upper portion of the lens-barrel and to the reinforcement material 11 using screws.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charged particle beam device provided with a vibration isolation mechanism.

[0002]

2. Description of the Related Art FIG. 1 shows a schematic example of a transmission electron microscope.

In FIG. 1, reference numeral 1 denotes a lens barrel, which includes an electron gun, a focusing lens,
An electron optical system such as a deflection system lens, a correction system lens for astigmatism correction, and the like, a sample holder for holding a sample to be observed, and the like are provided. Reference numeral 2 denotes an image observation room, which is provided with a fluorescent plate so that a sample image based on the electron beam transmitted through the sample is formed on the fluorescent plate.

A gantry 4 is installed on the floor 3, and the lens barrel 1 is placed on a base plate 5 installed on the gantry.
A basic microscope body comprising an image observation room 2 and the image observation room 2 is provided.

In the transmission electron microscope having such a configuration, there is a demand that the microscope main body including the gantry should be supported at the height of the center of gravity, but it is difficult to sufficiently meet the demand. Therefore, generally, in a transmission electron microscope, a vibration isolation mechanism (for example, a vibration isolation table 6 composed of a spring or the like) is used.
A, 6B, 6C, 6D (6C, 6D not shown)) are installed on the floor 3 as shown in FIG. 1, and a structure for supporting a lower portion of the gantry 4 is adopted.

[0006]

Now, recent transmission electron microscopes are composed of an extremely large number of parts, and the inside thereof is evacuated to an extremely low pressure and kept in a high vacuum state. It will be delivered to the place where it should be installed as it is completed at the factory. In addition, in such a loading, for example, when loading into a setting place such as a laboratory, it is often necessary to pass through a one-sided door, so that the width of the microscope main body including the stand is, for example, 800 mm. It is manufactured to be less than about. For this reason, the microscope body naturally becomes narrow and tall.

Here, as shown in FIG. 1, anti-vibration mounts 6A, 6B, 6C, 6D (6
In the case of the structure supported by C) and 6D), the center of gravity of the microscope main body is high and the width of the main body is narrow, so that the interval between the respective vibration isolation mounts must be narrowed.
The primary vibration mode of the vibration isolation system is as shown in FIG. The secondary vibration mode of the vibration isolation system is as shown in FIG. Now, in order to vibrate the vibration coming from the floor 3 to a low frequency, a mount having a low resonance frequency such as an air mount is preferably used as the anti-vibration mount. However, in the above structure,
There is a risk of unstable operation and a risk of the microscope body tipping over, and there is a problem in using a mount such as an air mount. Therefore, the vibration in the vertical direction (vertical direction in FIG. 1) has a smaller effect on the electron microscope image than the vibration in the horizontal direction (direction of the plane perpendicular to the vertical direction in FIG. 1), and is used for vibration isolation. By setting the spring constant and damping coefficient of the table to be higher in the vertical direction than in the horizontal direction, a method of suppressing rocking in the primary vibration mode and the secondary vibration mode of the vibration isolation system can be considered. Performance will be sacrificed to some extent.

On the other hand, as shown in FIG. 4, the primary vibration mode of the main body excluding the resonance frequency of the vibration isolation system begins to bend near the base of the lens barrel 1 and the upper end of the lens barrel bends most. The frequency of the primary vibration mode of the main body tends to decrease. Therefore, when vibration of a frequency that matches this primary mode is transmitted from the outside, the lens barrel will shake greatly due to resonance, unlike vibrations of other frequencies. That is, when the frequency of the primary vibration mode of the lens barrel main body is low, resonance is likely to occur with respect to vibration from the floor 3. Therefore, if the floor vibration has a frequency component equal to the first-order mode with a power equal to or higher than a certain level, it can be said that the amplitude of the vibration transmitted from the floor 3 can be reduced by the vibration isolation mounts 6A, 6B, 6C, and 6D. Also, due to the resonance of the gantry 4 above the anti-vibration mount, only the frequency components that match the first-order mode have large amplitudes, exceeding the allowable value. As a result, the observation image of the electron microscope is affected by the lens barrel vibration, which hinders the image observation and blurs the captured image.

The present invention solves such a problem and provides a novel charged particle beam device.

[0010]

Means for Solving the Problems A charged particle beam device of the present invention is a charged particle beam device in which a charged particle beam device main body is installed on a floor via a gantry, A reinforcing member detachably attached to the gantry is attached so as to extend outward from both side surfaces of the gantry, so that an overhang member can be suspended between the upper portion of the charged particle beam device main body and each reinforcing member. The vibration damping mounts are provided at least at two locations on the bottom surface near the operation side of the gantry and at the bottom surface near the attachment portion of the reinforcing member to the overhanging portion.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 5 shows a schematic example of an electron microscope as an example of the charged particle beam apparatus of the present invention. In the figure, the same reference numerals as those used in FIG. It is. Reference numerals 10 and 11 in the figure denote metal reinforcing members that can be attached to the gantry 4. The reinforcing member is formed in a katakana-shaped shape. For example, the two legs 10A and 10B of the reinforcing member 10 are behind the side surface of the gantry 4 (the side observed by the operator is the front side).
A mounting plate 12 having a plurality of screw holes is provided on one bottom surface of each leg so that the mounting plate 12 can be mounted on the upper and lower ends, respectively.
A and 12B are attached by welding or the like. It should be noted that a plurality of screw holes are formed in a corresponding portion of the gantry 4 to which the mounting plates 12A and 12B are applied when the reinforcing member 10 is attached to the gantry 4. A similar mounting plate is also attached to the two legs 11A and 11B of the other reinforcing member 11, and a corresponding portion of the mounting base 4 to which the mounting plate is applied when the plate is mounted on the mounting base 4 in the same manner as described above. Multiple screw holes are drilled.

Reference numerals 13 and 14 denote projecting members which are suspended between the other ends of the reinforcing members 10 and 11 and the upper part of the lens barrel 1. The overhanging member 13 has one end attached to the other end of the reinforcing member 10,
A mounting plate 15 having a plurality of screw holes is attached to the bottom surface of one end by welding or the like, and the other end is attached to the upper part of the lens barrel 1 so that the other end is attached to the top of the lens barrel 1. On the bottom surface, a mounting plate 16 having a plurality of screw holes is provided.
Is attached by welding or the like. It is needless to say that a plurality of screw holes are formed in a corresponding portion of the reinforcing member 10 to which the mounting plate 15 is applied when the projecting member 13 is mounted on the reinforcing member 10. A mounting ring 17 is provided on the upper part of the lens barrel, and a plurality of screw holes are formed in a corresponding portion of the mounting ring 19 to which the mounting plate 16 is applied when the overhang member 13 is mounted on the upper part of the lens barrel 1. Have been. Similarly, a mounting plate 18 having a plurality of screw holes is welded to the bottom surface of one end of the projecting member 14 so that one end of the projecting member 14 is attached to the other end of the reinforcing member 11. On the other bottom surface, a mounting plate 18 having a plurality of screw holes is mounted by welding or the like so that the other end is mounted on the upper part of the lens barrel 1. Have been. Further, when the overhang member 14 is attached to the reinforcing member 11, the reinforcing member 11
A plurality of screw holes are drilled in the corresponding part of
A plurality of screw holes are formed in a corresponding portion of the mounting ring 17 to which the mounting plate 19 is applied when mounted on the upper portion.

The legs 10A, 1 of the reinforcing members 10, 11
At both ends of the bottom of 1A, vibration isolation mounts 21, 22, 23, 24 such as coil springs, air springs or vibration isolation rubbers are provided.
Is attached. Note that anti-vibration mounts (not shown) are also attached to both ends on the front side (the side observed by the operator) of the gantry 4.

Thus, the microscope main body (the lens barrel 1 and the gantry 4 etc.) assembled in the factory is installed at a predetermined position on the floor 3 of the room to be installed. And each leg 10 of the reinforcing member 10
The reinforcing members 10 are fixed to the gantry 4 by fixing the mounting plates 12A and 12B of the gantry 4 to the upper and lower ends on the rear side of one side of the gantry 4, respectively. , 11B are fixed to the upper and lower ends of the rear side of the other side surface of the gantry 4 by screws, whereby the reinforcing member 11 is fixed to the gantry 4. With such fixation, the gantry 4 is located at two places in front of the gantry,
It is installed on the floor 3 via four anti-vibration mounts on the rear side.

Next, each mounting plate 1 of the projecting member 13
6, 15 are fixed to the rear side of the mounting ring 17 at the upper part of the lens barrel and the reinforcing member 10 by screws. It is fixed to the side and the reinforcing member 11 with screws.

As described above, the reinforcing members are attached to the pedestal and the projecting members are attached between the upper part of the lens barrel and the reinforcing members behind the both side surfaces of the gantry 4 on the front side of the electron microscope (observation side of the operator). This is because an operation unit console and the like are usually provided on the left and right sides of the parentheses, and there is little space for attaching a reinforcing member or a projecting member.

In this way, by suspending the projecting member between the reinforcing member attached to the gantry 4 and the upper part of the lens barrel,
The rigidity of the lens barrel can be dramatically increased. Moreover,
Since the projecting members are suspended from the two upper positions of the lens barrel at positions separated from the rear of the gantry, the rigidity of the lens barrel not only in the left-right direction but also in the front-rear direction can be increased. For this reason, the frequency of the primary vibration mode of the lens barrel 1 is greatly increased, and resonance with respect to vibration from the floor 3 is less likely to occur. That is, it is hard to be affected by the vibration from the floor 3, and the amplitude can be suppressed to be extremely small. As a result, the influence of the floor vibration on the microscope image is significantly reduced.

Further, since the lens barrel main body is carried into the installation place without attaching the reinforcing member and the overhanging member, and the reinforcement member and the overhanging member can be attached to the lens barrel main body after the carrying in, the laboratory and the like are provided. In addition to making it easier to carry in the installation location, the length of the reinforcing member can be increased, and the divergent angle of the overhanging flared member can be increased, so a high-performance vibration isolation member such as an air mount must be attached to the reinforcing member. Can be done. In addition, since the vibration isolating members can be attached to both ends of the long reinforcing member, the amplitude of the locking of the lens barrel can be suppressed, and there is no possibility of the lens barrel tipping over, so that a vibration isolating mount such as an air mount works stably. I can do it. As a result, transmission of floor vibration to the lens barrel main body can be suppressed low, and as a result, the influence of floor vibration on a microscope image is significantly reduced.

In addition, the passive anti-vibration mount cannot suppress a frequency corresponding to the frequency of vibration of the lens barrel main body among vibrations from the floor. Although the active vibration isolation system is applied to the system, the rigidity of the lens barrel can be significantly increased, so that the effect of the active vibration isolation system is further improved.
In the above example, two projecting members are provided, but three or more projecting members may be provided.

Further, the reinforcing member is not limited to the above example. For example, a structure as shown in FIG. In this case, mounting plates 25A, 25B, 25C, and 25D each having a screw hole are mounted on the gantry 4 side. Then, a screw is screwed into the reinforcing member 20 through a screw hole formed in each mounting plate, and the reinforcing member 20 is attached to the base 4.
Attach to

In the above example, four anti-vibration mounts are provided on the bottom surface of the reinforcing member, but the anti-vibration mounts at the ends farther from the gantry (mounts at both ends) are used as main mounts. When two mounts (mounts in the middle) on the side close to the gantry are used as auxiliary mounts, the latter auxiliary mount may be omitted. The mount at the intermediate portion may not be provided on the bottom of the gantry, but may be provided on the bottom of the gantry.
Also, in the above example, an electron microscope was taken as an example, but the present invention
Needless to say, the present invention can be applied to a charged particle beam device such as a scanning electron microscope, an electron beam drawing device, and an ion beam processing device. In an electron microscope, an image observation room corresponds to a drawing (processing) room in which a target to be drawn (processed) is set in an electron beam drawing apparatus or an ion beam processing apparatus. The drawing (processing) room and the sample room are referred to as a target room for convenience.

[Brief description of the drawings]

FIG. 1 shows a schematic example of an electron microscope.

FIG. 2 shows a primary vibration mode of a vibration isolation system.

FIG. 3 shows a secondary vibration mode of the vibration isolation system.

FIG. 4 shows a primary vibration mode of the lens barrel main body excluding the resonance frequency of the vibration isolation system.

FIG. 5 shows a schematic example of an electron microscope as an example of the charged particle beam device of the present invention.

FIG. 6 shows another example of a reinforcing member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Barrel 2 ... Image observation room 3 ... Floor 4 ... Stand 5 ... Base plate 6A, 6B, 6C, 6D, 21, 22, 23, 24 ... Anti-vibration mount 10, 11, 20 ... Reinforcement member 10A, 10B, 11A , 11B ... feet 12A, 12B, 15, 16, 18, 19 ... mounting plate 17 ... mounting ring

Claims (6)

[Claims] 1. A charged particle beam apparatus in which a charged particle beam apparatus main body is installed on a floor via a gantry,
A reinforcing member detachably attached to the gantry is mounted near the non-operating side of the gantry so as to extend outward from both side surfaces of the gantry, and is provided between the upper portion of the charged particle beam device main body and each reinforcing member. In addition, the overhanging member can be suspended, and at least the bottom surface near the operation side of the gantry should be
A charged particle beam apparatus wherein vibration isolation mounts are respectively provided at a position and a bottom portion near a portion where the reinforcing member is attached to a projecting portion. 2. The charged particle beam apparatus according to claim 1, wherein the charged particle beam main body includes an electron optical system lens barrel and an image observation room or a target room. 3. The charged particle beam device according to claim 1, wherein two or more projecting members are suspended. 4. The charged particle beam device according to claim 1, wherein at least the vibration isolation mount provided on the bottom surface near the overhang portion of the reinforcing member is an air mount. 5. The charged particle beam apparatus according to claim 1, wherein a projecting member is suspended between the counter-operation side of the upper portion of the charged particle beam main body and the reinforcing member. 6. The charged particle beam apparatus according to claim 1, wherein a reinforcing member is attached at least at upper and lower ends near the non-operation side of the gantry.